—— Has Jack finished his homework yet?
—— I have no idea； he ＿＿＿it this morning.
| A．was doing | B．had been doing |
| C．has done | D．did |
The students expect there ______ more reviewing classes before the final exam.
| A．is | B．to be | C．being | D．have been |
______ the secret of nature, the young scientist has little time for entertainment．
| A．Devoted to research | B．Devoted himself to research |
| C．Devoted to researching | D．Devoting to research |
_________ into a famous university made his parents very happy.
| A．Tom was admitted | B．Tom be admitted |
| C．If Tom was admitted | D．Tom’s being admitted |
________the working efficiency, the boss allows the employees to have a coffee break.
| A．Improving | B．To improve | C．Having improved | D．Improved |
Only when he read this novel for a second time ________ to appreciate its beauty.
| A．that he began | B．he began |
| C．had he begun | D．did he begin |