21. Of all the subjects, I like ______ physics best because it gives us ______ useful knowledge of things in science. And I'm desperate to turn ______ scientist in the future.

A. the ; a ; a               B. / ; an ; the            C./ ; a ; /                D. / ; the ; /

22. The life he was used to ________ greatly since 1992.

 A. change          B. has changed        C. changing         D. have changed

23. I think you two, _______Tom, ______ the broken glass.

 A. rather than; are to blame for             B. rather than; is to be blamed for

 C. other than; is responsible for             D. more than; are blamed for