1、— Jack?
— ____.
A. Present, Sir. B. I am, Sir C. Here, Sir D. Yes, Sir.
2、—What are you busy with?
— We are carrying out a research ____ the causes of cancer.
A. into B. onto C. to D. in
3、—____ the paper ?
— No, I have still got one page to finish.
A. Have you done B. Do you do C. Did you do D. Had you done
