Mr Wu is one of ________ in our school.

-----Why do many people like to ride bikes?----Because bikes not only need ________ space, but also cause _________accidents.

 The weather in Beijing in summer is ___than that in Shanghai. They are different.

--- Why did you buy two pairs of shoes? --- It was so hard to choose which was________, so I took them both.

---Can you tell me why you learn English so well ? ---It is very simple. _______ you work, ______ grades you will get.