diff --git a/module/libfib.nas b/module/libfib.nas
index 355a357..a42ed9b 100644
--- a/module/libfib.nas
+++ b/module/libfib.nas
@@ -1,4 +1,4 @@
-import.std.dylib;
+use std.dylib;
 
 var _dl = dylib.dlopen("libfib."~(os.platform()=="windows"?"dll":"so"));
 
diff --git a/module/libkey.nas b/module/libkey.nas
index a494c22..829e99c 100644
--- a/module/libkey.nas
+++ b/module/libkey.nas
@@ -1,4 +1,4 @@
-import.std.dylib;
+use std.dylib;
 
 var (
     kbhit,
diff --git a/module/libmat.nas b/module/libmat.nas
index cd06928..be7ef60 100644
--- a/module/libmat.nas
+++ b/module/libmat.nas
@@ -1,4 +1,4 @@
-import.std.dylib;
+use std.dylib;
 
 var _dl = dylib.dlopen("libmat."~(os.platform()=="windows"?"dll":"so"));
 
diff --git a/module/libsock.nas b/module/libsock.nas
index 15a57c1..fa6b356 100644
--- a/module/libsock.nas
+++ b/module/libsock.nas
@@ -1,4 +1,4 @@
-import.std.dylib;
+use std.dylib;
 
 var socket=func(){
     var lib=dylib.dlopen("libnasock"~(os.platform()=="windows"?".dll":".so"));
diff --git a/src/nasal_ast.h b/src/nasal_ast.h
index eb75e16..480e304 100644
--- a/src/nasal_ast.h
+++ b/src/nasal_ast.h
@@ -136,7 +136,7 @@ public:
     string_literal(const span& location, const std::string& str):
         expr(location, expr_type::ast_str), content(str) {}
     ~string_literal() override = default;
-    const std::string get_content() const {return content;}
+    const std::string& get_content() const {return content;}
     void accept(ast_visitor*) override;
 };
 
diff --git a/src/nasal_codegen.cpp b/src/nasal_codegen.cpp
index a3c5afc..a1018b4 100644
--- a/src/nasal_codegen.cpp
+++ b/src/nasal_codegen.cpp
@@ -307,7 +307,7 @@ void codegen::func_gen(function* node) {
 
 void codegen::call_gen(call_expr* node) {
     calc_gen(node->get_first());
-    if (code.back().op==op_callb) {
+    if (code.size() && code.back().op==op_callb) {
         return;
     }
     for(auto i : node->get_calls()) {
@@ -349,6 +349,8 @@ void codegen::call_id(identifier* node) {
         return;
     }
     die("undefined symbol \"" + name + "\"", node->get_location());
+    // generation failed, put a push nil operand here to fill the space
+    emit(op_pnil, index, node->get_location());
 }
 
 void codegen::call_hash_gen(call_hash* node) {
diff --git a/src/nasal_import.cpp b/src/nasal_import.cpp
index f5b31f0..f00abdb 100644
--- a/src/nasal_import.cpp
+++ b/src/nasal_import.cpp
@@ -24,19 +24,21 @@ linker::linker():
     }
 }
 
-std::string linker::get_path(call_expr* node) {
-    if (node->get_calls()[0]->get_type()==expr_type::ast_callf) {
-        auto tmp = (call_function*)node->get_calls()[0];
-        return ((string_literal*)tmp->get_argument()[0])->get_content();
+std::string linker::get_path(expr* node) {
+    if (node->get_type()==expr_type::ast_use) {
+        auto file_relative_path = std::string(".");
+        for(auto i : reinterpret_cast<use_stmt*>(node)->get_path()) {
+            file_relative_path += (is_windows()? "\\":"/") +i->get_name();
+        }
+        return file_relative_path + ".nas";
     }
-    auto fpath = std::string(".");
-    for(auto i : node->get_calls()) {
-        fpath += (is_windows()? "\\":"/") + ((call_hash*)i)->get_field();
-    }
-    return fpath + ".nas";
+    auto call_node = reinterpret_cast<call_expr*>(node);
+    auto tmp = reinterpret_cast<call_function*>(call_node->get_calls()[0]);
+    auto content = reinterpret_cast<string_literal*>(tmp->get_argument()[0]);
+    return content->get_content();
 }
 
-std::string linker::find_file(
+std::string linker::find_real_file_path(
     const std::string& filename, const span& location) {
     // first add file name itself into the file path
     std::vector<std::string> fpath = {filename};
@@ -56,65 +58,58 @@ std::string linker::find_file(
     // we will find lib.nas in nasal std directory
     if (filename=="lib.nas") {
         return is_windows()?
-            find_file("std\\lib.nas", location):
-            find_file("std/lib.nas", location);
+            find_real_file_path("std\\lib.nas", location):
+            find_real_file_path("std/lib.nas", location);
     }
     if (!show_path) {
         err.err("link",
             "in <" + location.file + ">: " +
             "cannot find file <" + filename + ">, " +
-            "use <-d> to get detail search path");
+            "use <-d> to get detail search path"
+        );
         return "";
     }
-    std::string paths = "";
+    auto paths = std::string("");
     for(const auto& i : fpath) {
         paths += "  -> " + i + "\n";
     }
     err.err("link",
         "in <" + location.file + ">: " +
-        "cannot find file <" + filename + "> in these paths:\n" + paths);
+        "cannot find file <" + filename + "> in these paths:\n" + paths
+    );
     return "";
 }
 
 bool linker::import_check(expr* node) {
-/*
-    call
-    |_id:import
-    |_callh:std
-    |_callh:file
-*/
-    if (node->get_type()!=expr_type::ast_call) {
-        return false;
-    }
-    auto tmp = (call_expr*)node;
-    if (tmp->get_first()->get_type()!=expr_type::ast_id) {
-        return false;
-    }
-    if (((identifier*)tmp->get_first())->get_name()!="import") {
-        return false;
-    }
-    if (!tmp->get_calls().size()) {
-        return false;
-    }
-    // import.xxx.xxx;
-    if (tmp->get_calls()[0]->get_type()==expr_type::ast_callh) {
-        for(auto i : tmp->get_calls()) {
-            if (i->get_type()!=expr_type::ast_callh) {
-                return false;
-            }
-        }
+    if (node->get_type()==expr_type::ast_use) {
         return true;
     }
-    // import("xxx");
-    if (tmp->get_calls().size()!=1) {
-        return false;
-    }
 /*
     call
     |_id:import
     |_call_func
       |_string:'filename'
 */
+    if (node->get_type()!=expr_type::ast_call) {
+        return false;
+    }
+    auto tmp = reinterpret_cast<call_expr*>(node);
+    auto first_expr = tmp->get_first();
+    if (first_expr->get_type()!=expr_type::ast_id) {
+        return false;
+    }
+    if (reinterpret_cast<identifier*>(first_expr)->get_name()!="import") {
+        return false;
+    }
+    if (!tmp->get_calls().size()) {
+        return false;
+    }
+
+    // import("xxx");
+    if (tmp->get_calls().size()!=1) {
+        return false;
+    }
+
     if (tmp->get_calls()[0]->get_type()!=expr_type::ast_callf) {
         return false;
     }
@@ -139,17 +134,6 @@ bool linker::exist(const std::string& file) {
     return false;
 }
 
-u16 linker::find(const std::string& file) {
-    for(usize i = 0; i<files.size(); ++i) {
-        if (files[i]==file) {
-            return static_cast<u16>(i);
-        }
-    }
-    std::cerr << "unreachable: using this method incorrectly\n";
-    std::exit(-1);
-    return UINT16_MAX;
-}
-
 bool linker::check_self_import(const std::string& file) {
     for(const auto& i : module_load_stack) {
         if (file==i) {
@@ -176,24 +160,26 @@ void linker::link(code_block* new_tree_root, code_block* old_tree_root) {
     old_tree_root->get_expressions().clear();
 }
 
-code_block* linker::import_regular_file(call_expr* node) {
-    lexer lex;
-    parse par;
+code_block* linker::import_regular_file(expr* node) {
     // get filename
     auto filename = get_path(node);
-    // clear this node
-    for(auto i : node->get_calls()) {
-        delete i;
+
+    // clear import("xxx/xxx.nas") node
+    if (node->get_type()!=expr_type::ast_use) {
+        auto cast_node = reinterpret_cast<call_expr*>(node);
+        for(auto i : cast_node->get_calls()) {
+            delete i;
+        }
+        cast_node->get_calls().clear();
+        const auto& location = cast_node->get_first()->get_location();
+        delete cast_node->get_first();
+        cast_node->set_first(new nil_expr(location));
+        // this will make node to call_expr(nil),
+        // will not be optimized when generating bytecodes
     }
-    node->get_calls().clear();
-    auto location = node->get_first()->get_location();
-    delete node->get_first();
-    node->set_first(new nil_expr(location));
-    // this will make node to call_expr(nil),
-    // will not be optimized when generating bytecodes
 
     // avoid infinite loading loop
-    filename = find_file(filename, node->get_location());
+    filename = find_real_file_path(filename, node->get_location());
     if (!filename.length()) {
         return new code_block({0, 0, 0, 0, filename});
     }
@@ -208,27 +194,27 @@ code_block* linker::import_regular_file(call_expr* node) {
     
     module_load_stack.push_back(filename);
     // start importing...
-    if (lex.scan(filename).geterr()) {
+    lexer nasal_lexer;
+    parse nasal_parser;
+    if (nasal_lexer.scan(filename).geterr()) {
         err.err("link", "error occurred when analysing <" + filename + ">");
         return new code_block({0, 0, 0, 0, filename});
     }
-    if (par.compile(lex).geterr())  {
+    if (nasal_parser.compile(nasal_lexer).geterr())  {
         err.err("link", "error occurred when analysing <" + filename + ">");
         return new code_block({0, 0, 0, 0, filename});
     }
-
-    auto parse_result = par.swap(nullptr);
+    // swap result out
+    auto parse_result = nasal_parser.swap(nullptr);
 
     // check if parse result has 'import'
-    auto result = load(parse_result, find(filename));
+    auto result = load(parse_result, filename);
     module_load_stack.pop_back();
     return result;
 }
 
 code_block* linker::import_nasal_lib() {
-    lexer lex;
-    parse par;
-    auto filename = find_file("lib.nas", {0, 0, 0, 0, files[0]});
+    auto filename = find_real_file_path("lib.nas", {0, 0, 0, 0, files[0]});
     if (!filename.length()) {
         return new code_block({0, 0, 0, 0, filename});
     }
@@ -240,22 +226,24 @@ code_block* linker::import_nasal_lib() {
     }
     
     // start importing...
-    if (lex.scan(filename).geterr()) {
+    lexer nasal_lexer;
+    parse nasal_parser;
+    if (nasal_lexer.scan(filename).geterr()) {
         err.err("link",
             "error occurred when analysing library <" + filename + ">"
         );
         return new code_block({0, 0, 0, 0, filename});
     }
-    if (par.compile(lex).geterr())  {
+    if (nasal_parser.compile(nasal_lexer).geterr())  {
         err.err("link",
             "error occurred when analysing library <" + filename + ">"
         );
         return new code_block({0, 0, 0, 0, filename});
     }
-
-    auto parse_result = par.swap(nullptr);
+    // swap result out
+    auto parse_result = nasal_parser.swap(nullptr);
     // check if library has 'import' (in fact it should not)
-    return load(parse_result, find(filename));
+    return load(parse_result, filename);
 }
 
 std::string linker::generate_module_name(const std::string& file_path) {
@@ -314,6 +302,12 @@ std::string linker::generate_module_name(const std::string& file_path) {
             "will not be easily accessed."
         );
     }
+    if (module_name.length() && module_name.find("-")!=std::string::npos) {
+        err.warn("link",
+            "get module <" + module_name + "> from <" + file_path + ">, " +
+            "will not be easily accessed."
+        );
+    }
     return module_name;
 }
 
@@ -353,8 +347,8 @@ definition_expr* linker::generate_module_definition(code_block* block) {
     return def;
 }
 
-code_block* linker::load(code_block* program_root, u16 fileindex) {
-    auto tree = new code_block({0, 0, 0, 0, files[fileindex]});
+code_block* linker::load(code_block* program_root, const std::string& filename) {
+    auto tree = new code_block({0, 0, 0, 0, filename});
     // load library, this ast will be linked with root directly
     // so no extra namespace is generated
     if (!lib_loaded) {
@@ -370,12 +364,13 @@ code_block* linker::load(code_block* program_root, u16 fileindex) {
         if (!import_check(import_ast_node)) {
             break;
         }
-        auto module_code_block = import_regular_file((call_expr*)import_ast_node);
+        auto module_code_block = import_regular_file(import_ast_node);
+        // this location should not be a reference, may cause use after free!
+        const auto location = import_ast_node->get_location();
         // after importing the regular file as module, delete this node
-        const auto loc = import_ast_node->get_location();
         delete import_ast_node;
         // and replace the node with null_expr node
-        import_ast_node = new null_expr(loc);
+        import_ast_node = new null_expr(location);
         // then we generate a function warping the code block,
         // and export the necessary global symbols in this code block
         // by generate a return statement, with a hashmap return value
@@ -397,7 +392,7 @@ const error& linker::link(
     // scan root and import files
     // then generate a new ast and return to import_ast
     // the main file's index is 0
-    auto new_tree_root = load(parse.tree(), 0);
+    auto new_tree_root = load(parse.tree(), self);
     auto old_tree_root = parse.swap(new_tree_root);
     delete old_tree_root;
     return err;
diff --git a/src/nasal_import.h b/src/nasal_import.h
index fc53fe9..c09eabe 100644
--- a/src/nasal_import.h
+++ b/src/nasal_import.h
@@ -36,18 +36,17 @@ private:
 private:
     bool import_check(expr*);
     bool exist(const std::string&);
-    u16 find(const std::string&);
     bool check_self_import(const std::string&);
     std::string generate_self_import_path(const std::string&);
     void link(code_block*, code_block*);
-    std::string get_path(call_expr*);
-    std::string find_file(const std::string&, const span&);
-    code_block* import_regular_file(call_expr*);
+    std::string get_path(expr*);
+    std::string find_real_file_path(const std::string&, const span&);
+    code_block* import_regular_file(expr*);
     code_block* import_nasal_lib();
     std::string generate_module_name(const std::string&);
     return_expr* generate_module_return(code_block*);
     definition_expr* generate_module_definition(code_block*);
-    code_block* load(code_block*, u16);
+    code_block* load(code_block*, const std::string&);
 
 public:
     linker();
diff --git a/std/fg_env.nas b/std/fg_env.nas
index 47d435d..81bfb92 100644
--- a/std/fg_env.nas
+++ b/std/fg_env.nas
@@ -1,6 +1,6 @@
 # flightgear developer environments simulator (beta)
 # ValKmjolnir 2022
-import.std.runtime;
+use std.runtime;
 
 println("-------------------------------------------------------------");
 println(" FlightGear simulated-env for developers project, since 2019");
diff --git a/std/lib.nas b/std/lib.nas
index 95cb4a6..ce2afef 100644
--- a/std/lib.nas
+++ b/std/lib.nas
@@ -1,13 +1,13 @@
 # lib.nas
 # 2019 ValKmjolnir
 
-import.std.coroutine;
-import.std.math;
-import.std.string;
-import.std.io;
-import.std.os;
-import.std.bits;
-import.std.unix;
+use std.coroutine;
+use std.math;
+use std.string;
+use std.io;
+use std.os;
+use std.bits;
+use std.unix;
 
 # print is used to print all things in nasal, try and see how it works.
 # this function uses std::cout to output logs.
diff --git a/test/ascii-art.nas b/test/ascii-art.nas
index 9e8335f..2f04b89 100644
--- a/test/ascii-art.nas
+++ b/test/ascii-art.nas
@@ -1,5 +1,5 @@
-import.std.padding;
-import.std.process_bar;
+use std.padding;
+use std.process_bar;
 
 var char_ttf=[
     ["    ","    ","    ","    ","    ","    "],
diff --git a/test/auto_crash.nas b/test/auto_crash.nas
index b277c4b..3700395 100644
--- a/test/auto_crash.nas
+++ b/test/auto_crash.nas
@@ -1,5 +1,5 @@
 # Road check and auto pilot by ValKmjolnir
-import.std.fg_env;
+use std.fg_env;
 
 var props = fg_env.props;
 var geodinfo = fg_env.geodinfo;
diff --git a/test/bfs.nas b/test/bfs.nas
index 4568d6b..1520e7a 100644
--- a/test/bfs.nas
+++ b/test/bfs.nas
@@ -1,4 +1,4 @@
-import.std.queue;
+use std.queue;
 
 rand(time(0));
 var pixel=[' ','#','.','*'];
diff --git a/test/bp.nas b/test/bp.nas
index f685a68..88dadf9 100644
--- a/test/bp.nas
+++ b/test/bp.nas
@@ -1,4 +1,4 @@
-import.std.mat;
+use std.mat;
 
 rand(time(0));
 
diff --git a/test/burningship.nas b/test/burningship.nas
index a247522..7075059 100644
--- a/test/burningship.nas
+++ b/test/burningship.nas
@@ -1,4 +1,4 @@
-import.std.process_bar;
+use std.process_bar;
 
 var ppm = func(filename, width, height, RGB) {
     # P3 use ASCII number
diff --git a/test/calc.nas b/test/calc.nas
index 440701e..516a2db 100644
--- a/test/calc.nas
+++ b/test/calc.nas
@@ -1,5 +1,5 @@
-import.std.padding;
-import.std.file;
+use std.padding;
+use std.file;
 
 var source=file.find_all_files_with_extension("./src","cpp","h");
 sort(source,func(a,b){return cmp(a,b)<0});
diff --git a/test/console3D.nas b/test/console3D.nas
index ccc3332..9226d68 100644
--- a/test/console3D.nas
+++ b/test/console3D.nas
@@ -21,8 +21,8 @@
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
-import.module.libmat;
-import.std.runtime;
+use module.libmat;
+use std.runtime;
 
 func(){
     # allocate more spaces
diff --git a/test/coroutine.nas b/test/coroutine.nas
index 4d6c09a..3eeacbb 100644
--- a/test/coroutine.nas
+++ b/test/coroutine.nas
@@ -1,7 +1,7 @@
 # coroutine.nas by ValKmjolnir
 # 2022/5/19
-import.std.process_bar;
-import.std.padding;
+use std.process_bar;
+use std.padding;
 
 if(os.platform()=="windows"){
     system("chcp 65001");
diff --git a/test/datalog.nas b/test/datalog.nas
index 6757856..eab13ef 100644
--- a/test/datalog.nas
+++ b/test/datalog.nas
@@ -1,5 +1,5 @@
-import.std.padding;
-import.std.process_bar;
+use std.padding;
+use std.process_bar;
 
 var mess=func(vec) {
     srand();
diff --git a/test/donuts.nas b/test/donuts.nas
index 5fe5c27..58dac11 100644
--- a/test/donuts.nas
+++ b/test/donuts.nas
@@ -1,4 +1,4 @@
-import.std.runtime;
+use std.runtime;
 
 var mod = math.mod;
 
diff --git a/test/feigenbaum.nas b/test/feigenbaum.nas
index b235ae8..e7aab39 100644
--- a/test/feigenbaum.nas
+++ b/test/feigenbaum.nas
@@ -1,4 +1,4 @@
-import.std.process_bar;
+use std.process_bar;
 
 var ppm = func(filename, width, height, RGB) {
     # P3 use ASCII number
diff --git a/test/flush_screen.nas b/test/flush_screen.nas
index 2c24113..499797a 100644
--- a/test/flush_screen.nas
+++ b/test/flush_screen.nas
@@ -1,4 +1,4 @@
-import.module.libkey;
+use module.libkey;
 
 srand();
 
diff --git a/test/gc_test.nas b/test/gc_test.nas
index b7e223c..fd3f28e 100644
--- a/test/gc_test.nas
+++ b/test/gc_test.nas
@@ -1,4 +1,4 @@
-import.std.runtime;
+use std.runtime;
 
 var test_func = func(test_processes...) {
     var test_process_total = maketimestamp();
diff --git a/test/hexdump.nas b/test/hexdump.nas
index dcfaafc..d77c15e 100644
--- a/test/hexdump.nas
+++ b/test/hexdump.nas
@@ -1,7 +1,7 @@
 # hexdump.nas by ValKmjolnir
 # 2021/8/13
-import.std.file;
-import.std.runtime;
+use std.file;
+use std.runtime;
 
 # init
 var hex=func(){
diff --git a/test/httptest.nas b/test/httptest.nas
index be0f6bb..3b8fcaf 100644
--- a/test/httptest.nas
+++ b/test/httptest.nas
@@ -1,4 +1,4 @@
-import.module.libsock;
+use module.libsock;
 
 var socket = libsock.socket;
 
diff --git a/test/json.nas b/test/json.nas
index d5be934..fbc053d 100644
--- a/test/json.nas
+++ b/test/json.nas
@@ -1,5 +1,5 @@
-import.std.json;
-import.std.process_bar;
+use std.json;
+use std.process_bar;
 
 var ss = json.stringify({
     vec:[0,1,2],
diff --git a/test/jsonrpc.nas b/test/jsonrpc.nas
index f976fc5..56b4484 100644
--- a/test/jsonrpc.nas
+++ b/test/jsonrpc.nas
@@ -1,6 +1,6 @@
-import.module.libsock;
-import.std.json;
-import.std.runtime;
+use module.libsock;
+use std.json;
+use std.runtime;
 
 var socket = libsock.socket;
 
diff --git a/test/life.nas b/test/life.nas
index 9e29298..3b6fb0e 100644
--- a/test/life.nas
+++ b/test/life.nas
@@ -1,5 +1,5 @@
-import.std.process_bar;
-import.std.runtime;
+use std.process_bar;
+use std.runtime;
 
 var new_map=func(width,height){
     var tmp=[];
diff --git a/test/md5compare.nas b/test/md5compare.nas
index 7ffca1b..29cd027 100644
--- a/test/md5compare.nas
+++ b/test/md5compare.nas
@@ -1,6 +1,6 @@
-import.test.md5_self;
-import.std.process_bar;
-import.std.file;
+use test.md5_self;
+use std.process_bar;
+use std.file;
 
 srand();
 
diff --git a/test/module_test.nas b/test/module_test.nas
index da9678c..109ceda 100644
--- a/test/module_test.nas
+++ b/test/module_test.nas
@@ -1,5 +1,5 @@
-import.std.dylib;
-import.module.libfib;
+use std.dylib;
+use module.libfib;
 
 println(keys(libfib));
 libfib.test_ghost();
diff --git a/test/occupation.nas b/test/occupation.nas
index 9ea4302..99e5aa0 100644
--- a/test/occupation.nas
+++ b/test/occupation.nas
@@ -1,6 +1,6 @@
-import.std.process_bar;
-import.module.libkey;
-import.std.runtime;
+use std.process_bar;
+use module.libkey;
+use std.runtime;
 
 var is_windows_platform=os.platform()=="windows";
 var is_macos_platform=os.platform()=="macOS";
diff --git a/test/ppmgen.nas b/test/ppmgen.nas
index f200056..857b5e4 100644
--- a/test/ppmgen.nas
+++ b/test/ppmgen.nas
@@ -1,4 +1,4 @@
-import.std.process_bar;
+use std.process_bar;
 
 var ppm = func(filename, width, height, RGB) {
     # P3 use ASCII number
diff --git a/test/scalar.nas b/test/scalar.nas
index 3e6039f..e2c9feb 100644
--- a/test/scalar.nas
+++ b/test/scalar.nas
@@ -1,4 +1,4 @@
-import.std.runtime;
+use std.runtime;
 
 # basic type
 nil;
diff --git a/test/self_ref_module/a.nas b/test/self_ref_module/a.nas
index d84ea33..a25d913 100644
--- a/test/self_ref_module/a.nas
+++ b/test/self_ref_module/a.nas
@@ -1,5 +1,5 @@
 # this will cause error
-# import.b;
+# use b;
 
 println("init a");
 var a = "hello";
\ No newline at end of file
diff --git a/test/self_ref_module/b.nas b/test/self_ref_module/b.nas
index dcace50..a8a6634 100644
--- a/test/self_ref_module/b.nas
+++ b/test/self_ref_module/b.nas
@@ -1,3 +1,3 @@
-import.a;
+use a;
 
 println("init b");
\ No newline at end of file
diff --git a/test/self_ref_module/c.nas b/test/self_ref_module/c.nas
index cb81e5d..039b2f7 100644
--- a/test/self_ref_module/c.nas
+++ b/test/self_ref_module/c.nas
@@ -1,3 +1,3 @@
-import.b;
+use b;
 
 println("init c");
\ No newline at end of file
diff --git a/test/self_ref_module/main.nas b/test/self_ref_module/main.nas
index 36b0a1a..da69dff 100644
--- a/test/self_ref_module/main.nas
+++ b/test/self_ref_module/main.nas
@@ -1,6 +1,6 @@
-import.c;
-import.a;
-import.b;
+use c;
+use a;
+use b;
 
 println(a);
 println(b);
diff --git a/test/snake.nas b/test/snake.nas
index 08b82a9..27babbb 100644
--- a/test/snake.nas
+++ b/test/snake.nas
@@ -1,6 +1,6 @@
-import.module.libkey;
-import.std.list;
-import.std.runtime;
+use module.libkey;
+use std.list;
+use std.runtime;
 
 var game=func(x,y){
     rand(time(0));
diff --git a/test/tetris.nas b/test/tetris.nas
index e2e1cf4..0d8ccc9 100644
--- a/test/tetris.nas
+++ b/test/tetris.nas
@@ -1,5 +1,5 @@
-import.module.libkey;
-import.std.runtime;
+use module.libkey;
+use std.runtime;
 
 var color=[
     "\e[31m","\e[32m","\e[33m","\e[34m","\e[35m","\e[36m",
diff --git a/test/watchdog.nas b/test/watchdog.nas
index a27813c..f89c59a 100644
--- a/test/watchdog.nas
+++ b/test/watchdog.nas
@@ -1,4 +1,4 @@
-import.std.runtime;
+use std.runtime;
 
 var os_time=func(){
     return "[\e[33;1m"~os.time()~"\e[0m] ";
diff --git a/test/word_collector.nas b/test/word_collector.nas
index 87e7151..32d6916 100644
--- a/test/word_collector.nas
+++ b/test/word_collector.nas
@@ -1,4 +1,4 @@
-import.std.runtime;
+use std.runtime;
 
 var to_lower=func(s){
     var tmp="";
diff --git a/tools/search_file.nas b/tools/search_file.nas
index bce4c1e..72e52d2 100644
--- a/tools/search_file.nas
+++ b/tools/search_file.nas
@@ -1,4 +1,4 @@
-import.std.file;
+use std.file;
 
 var tips = func() {
     println("usage:");