on used to work in a remote mountain villageschool, which is only on foot.

If you want to change for a red one you’ll have to pay___________ $ 20

It is a pity that you didn’t the lecture by Qian Zhiliang. It is wonderful!

What do you think of genetically modified food (转基因食品) —We all think ______ is careless ______ some scientists to say it is safe before doing any experiment.

_____________ do you go to the zoo —Never. I hate the smell.