Unit 4 单元测试题Written test part (共95分). 单项选择(每小题1分,共15分)从A、B、C、D四个选项中选出可以填入空白处的最佳答案。( ) 21. Parents play an important role _ their childrens learning.A. on B. for C. in D. with( ) 22. Dale is much better at _ than Peter, because he performs plays each school year.A. acting B. act C. swimming D. swim ( ) 23. Mary helped me buy a ticket. She _ an hour ago.A. gave it to me B. gives me itC. gives it me D.