Module 2 DNA—the Secret of Life 
单元测试题
单项选择(1X15)
21------ What do you suppose made her so happy?
------ ____________  the entrance examination.
A. Because of pasting      B. Because he pasted    C. having been past    D. having pasted
22.I lay in the sofa, enjoying the beautiful music Jack had  __________ out of his DVD.
A. come                 B. it come             C. it coming         D. coming
23.I’d love ________ to your party last Sunday if not because of the unexpected guests.
A to go                   B. going               C. having gone      D. to have