Robert is said _______ abroad, but I don’t know what country he studied in.
| A．to have studied | B．to study |
| C．to be studying | D．to have been studying |
______ I admit that there are problems, I don't agree that they cannot be solved.
| A．As | B．If | C．While | D．When |
Small _____ it is, the pen is a most useful tool.
| A．because | B．so | C．if | D．as |
______ it is getting dark.，we’d better hurry
| A．And | B．But | C．Since | D．Unless |
_____ she was very tired, she went on working.
| A．As | B．Although | C．Even | D．In spite of |
This is the factory my father worked ten years ago.
| A．where | B．that | C．which | D．when |