The president's message to students was simple: study hard,pay attention in class and embrace the opportunity to learn.

VOA: standard.2009.09.08

It's not a simple matter. Imagine what it would be like if you had to learn about sixty such things?

绝不是个简单的事,想象一下如果你得学,六十个字母会是什么状况

耶鲁公开课 - 古希腊历史简介课程节选

Is there is very simple and it's a great one to learn.

s there 是非常简单而有效的句型。

Is there 课堂 - SpeakingMax英语口语达人