Update README.md

Author: BernardXiong

README.md

@@ -3,17 +3,17 @@
 [![Build Status](https://travis-ci.org/RT-Thread/rt-thread.svg)](https://travis-ci.org/RT-Thread/rt-thread)
 [![Gitter](https://badges.gitter.im/Join Chat.svg)](https://gitter.im/RT-Thread/rt-thread?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
-RT-Thread is an open source real-time operating system for embedded devices from China. RT-Thread RTOS is a scalable real-time operating system: a tiny kernel for ARM Cortex-M0, Cortex-M3/4/7, or a rich feature system like ARM Cortex-A8, ARM Cortex-A9 DualCore etc. 
+RT-Thread is an open source real-time operating system for embedded devices from China, which has strong scalability: from a tiny kernel running on a tiny core, for example ARM Cortex-M0, or Cortex-M3/4/7, to a rich feature system running on ARM Cortex-A8, ARM Cortex-A9 DualCore etc.
 
 ## Overview ##
 
-RT-Thread RTOS like a traditional real-time operating system. The kernel has real-time multi-task scheduling, semaphore, mutex, mail box, message queue etc. However, it has two different things:
+RT-Thread RTOS like a traditional real-time operating system. The kernel has real-time multi-task scheduling, semaphore, mutex, mail box, message queue etc. However, it has three different things:
 
 * Device Driver;
 * Component;
 * Application Module
 
-The device driver is more like a driver framework, UART, IIC, SPI, SDIO, USB device/host, EMAC, MTD NAND etc. The developer can easily add low level driver and board configuration, then he/she can use lots of features. 
+The device driver is more like a driver framework, UART, IIC, SPI, SDIO, USB device/host, EMAC, MTD NAND etc. The developer can easily add low level driver and board configuration, then combined with the upper framework, he/she can use lots of features.
 
 The Component is a software concept upon RT-Thread kernel, for example a shell (finsh/msh shell), virtual file system (FAT, YAFFS, UFFS, ROM/RAM file system etc), TCP/IP protocol stack (lwIP), POSIX (thread) interface etc. One component must be a directory under RT-Thread/Components and one component can be descripted by a SConscript file (then be compiled and linked into the system).
 
@@ -41,7 +41,6 @@ As a special exception, including RT-Thread RTOS header files in a file, instant
 ## Usage ##
 
 RT-Thread RTOS uses [scons](http://www.scons.org) as building system. Therefore, please install scons and Python 2.7 firstly. 
-
 So far, the RT-Thread scons building system support the command line compile or generate some IDE's project. There are some option varaibles in the scons building script (rtconfig.py):
 
 * ```CROSS_TOOL``` the compiler which you want to use, gcc/keil/iar. 
@@ -58,7 +57,7 @@ When you set these variables correctly, you can use command:
 under BSP directory to simplely compile RT-Thread RTOS.
 
 If you want to generate the IDE's project file, you can use command:
-s
+
     scons --target=mdk/mdk4/mdk5/iar/cb -s 
 
 to generate the project file. 
@@ -67,4 +66,4 @@ NOTE: RT-Thread scons building system will tailor the system according to your r
 
 ## Contribution ##
 
-Thank all of RT-Thread Developers. 
+Please refer the contributors in the github. Thank all of RT-Thread Developers.