diff --git a/docs/en/02-intro/index.md b/docs/en/02-intro/index.md
index b4636e54a6..821fc7c95e 100644
--- a/docs/en/02-intro/index.md
+++ b/docs/en/02-intro/index.md
@@ -11,21 +11,33 @@ This section introduces the major features, competitive advantages, typical use-
 
 The major features are listed below:
 
-1. While TDengine supports [using SQL to insert](/develop/insert-data/sql-writing), it also supports [Schemaless writing](/reference/schemaless/) just like NoSQL databases. TDengine also supports standard protocols like [InfluxDB LINE](/develop/insert-data/influxdb-line)，[OpenTSDB Telnet](/develop/insert-data/opentsdb-telnet), [OpenTSDB JSON ](/develop/insert-data/opentsdb-json) among others.
-2. TDengine supports seamless integration with third-party data collection agents like [Telegraf](/third-party/telegraf)，[Prometheus](/third-party/prometheus)，[StatsD](/third-party/statsd)，[collectd](/third-party/collectd)，[icinga2](/third-party/icinga2), [TCollector](/third-party/tcollector), [EMQX](/third-party/emq-broker), [HiveMQ](/third-party/hive-mq-broker). These agents can write data into TDengine with simple configuration and without a single line of code. 
-3. Support for [all kinds of queries](/develop/query-data), including aggregation, nested query, downsampling, interpolation and others.
-4. Support for [user defined functions](/develop/udf).
-5. Support for [caching](/develop/cache). TDengine always saves the last data point in cache, so Redis is not needed in some scenarios.
-6. Support for [continuous query](../develop/stream).
-7. Support for [data subscription](../develop/tmq) with the capability to specify filter conditions.
-8. Support for [cluster](../deployment/), with the capability of increasing processing power by adding more nodes. High availability is supported by replication. 
-9. Provides an interactive [command-line interface](/reference/taos-shell) for management, maintenance and ad-hoc queries.
-10. Provides many ways to [import](/operation/import) and [export](/operation/export) data.
-11. Provides [monitoring](/operation/monitor) on running instances of TDengine.
-12. Provides [connectors](/reference/connector/) for [C/C++](/reference/connector/cpp), [Java](/reference/connector/java), [Python](/reference/connector/python), [Go](/reference/connector/go), [Rust](/reference/connector/rust), [Node.js](/reference/connector/node) and other programming languages.
-13. Provides a [REST API](/reference/rest-api/).
-14. Supports seamless integration with [Grafana](/third-party/grafana) for visualization.
-15. Supports seamless integration with Google Data Studio.
+1. Insert data
+    * supports [using SQL to insert](/develop/insert-data/sql-writing).
+    * supports [schemaless writing](/reference/schemaless/) just like NoSQL databases. It also supports standard protocols like [InfluxDB LINE](/develop/insert-data/influxdb-line)，[OpenTSDB Telnet](/develop/insert-data/opentsdb-telnet), [OpenTSDB JSON ](/develop/insert-data/opentsdb-json) among others.
+    * supports seamless integration with third-party tools like [Telegraf](../data-in/telegraf)，[Prometheus](../data-in/prometheus)，they can write data into TDengine with simple configuration and without a single line of code. 
+2. Query data
+    * supports standard SQL, including nested query.
+    * supports [time series specific functions](../taos-sql/function/#time-series-extensions) and [time series specific queries](../taos-sql/distinguished), like downsampling, interpolation, cumulated sum, time weighted average, state window, session window and many others.
+    * supports [user defined functions](../taos-sql/udf).
+3. [caching](../taos-sql/database): TDengine always saves the last data point in cache, so Redis is not needed for time-series data processing.
+4. [stream processing](../taos-sql/stream): not only is the continuous query is supported, but TDengine also supports even driven stream processing, so Flink or spark is not needed for time-series daata processing. 
+5. [data subscription](../taos-sql/tmq): application can subscribe a table or a set of tables. API is the same as Kafka, but you can specify filter conditions.
+6. Visulization
+    * supports seamless integration with [Grafana](../visual/grafana) for visualization.
+    * supports seamless integration with Google Data Studio.
+7. Cluster
+    * supports [cluster](../deployment/), with the capability of increasing processing power by adding more nodes. 
+    * Supports [deployment on Kubernetes](../deployment/k8s/)
+    * upports high availability is via replication and RAFT. 
+8. Administration
+    * provides [monitoring](/operation/monitor) on running instances of TDengine.
+    * provides many ways to [import](/operation/import) and [export](/operation/export) data.
+9. Tools
+    * provides an interactive [command-line interface](/reference/taos-shell) for management, maintenance and ad-hoc queries.
+    * provides a tool [taosBenchmark](/reference/taosbenchmark/) for testing the performance of TDengine.
+10. Programming
+    * provides [connectors](/reference/connector/) for [C/C++](/reference/connector/cpp), [Java](/reference/connector/java), [Python](/reference/connector/python), [Go](/reference/connector/go), [Rust](/reference/connector/rust), [Node.js](/reference/connector/node) and other programming languages.
+    * provides a [REST API](/reference/rest-api/).
 
 For more details on features, please read through the entire documentation.