It still remains a question _____ life exists on any other planet in the solar system.
| A．why | B．whether | C．how | D．where |
How could you ________ such a fantastic job when you have been out of work for months?
| A．turn off | B．turn in |
| C．turn down | D．turn to |
The manager put up a notice to keep the staff ________of what to do this week．
| A．inform | B．informing |
| C．informed | D．to inform |
_____ I can’t fully understand what his music conveys, his performance is quite impressive.
| A．As | B．Since | C．If | D．While |
His uncle went abroad in 2010, and ________since.
| A．has not been heard of |
| B．had not been heard of |
| C．had not heard of |
| D．has not heard of |
It is required in the library regulations that any book borrowed __________ by due time, or the borrower will be fined.
| A．return | B．be returned |
| C．returns | D．is returned |