10 years ago， _________ only one classroom building in our school. And in 10 years， _________ five classroom buildings in our school.

38She is crazy _____ the film star, while her brother is crazy _____ surfing

Does your brother study in Beijing University?—- No, not nowBut he ________ there for 7 years

Shanghai World Expo was the most important_____ in China in 2010.

You never know how much difficulty we had _________________ the problem. Luckily, we try to solve it with Mrs Wu’s help.