bugfix:1.修正语法错误; 2.调整长句描述。

thanks to finian(http://weibo.com/n/finian) for picking out the mistake http://weibo.com/2041028560/Bx9ugj6xm?type=repost) 挑小毛病，it's *an* application
Signed-off-by: lingyi <e3.gemini@qq.com>