Adjust documents.

README.md

@@ -31,6 +31,10 @@ The core features are following.
 
 <img src="https://skywalkingtest.github.io/page-resources/6_overview.png"/>
 
+SkyWalking supports to collect telemetry (traces and metrics) data from different sources, 
+in order to provide more options
+for different scenarios. For better understanding, read our documents.
+
 
 # Document
 - [Documents in English](docs/README.md)

docs/en/concepts-and-designs/README.md

@@ -2,7 +2,7 @@
 Concepts and Designs help you to learn and understand the SkyWalking and the landscape.
 
 - What is SkyWalking?
-  - [Overview and Core concepts](overview.md). Provides a high-level description and introduction, including the problems it solves.
+  - [Overview and Core concepts](overview.md). Provides a high-level description and introduction, including the problems the project solves.
   - [Project Goals](project-goals.md). Provides the goals, which SkyWalking is trying to focus and provide features about them.
 
 After you read the above documents, you should understand the SkyWalking basic goals. Now, you can choose which following parts