Did you meet with the famous space hero , Yang Liwei ?—I had come here earlier !

29. It is known to us that doing eye exercises ________ our eyes, and that is to say, our eyes can ________ doing eye exercises.

_____ do you like science—Because it’s interesting.

His classmates offered him their congratulations ______ his successful performance.

Which would you like to visit, Shanghai Expo Garden or Beijing Bird Nest— ______. I prefer to enjoy the 2010 FIFA World Cup at home.