从 A,B,C,D四个选项中,选出可以填入空白处的最佳答案: 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 4、_____ in all parts of the state, pines are the most common trees in Georgia . A. Found B. Finding them C. To find them D. They are found 5、They ___ the game. A. are disappointed at losing B. disappoint C. are disappointing D. are disappointed |