Before the firemen arrived, the whole wooden house had already been completely ______ in the big fire.
| A．injured |
| B．wounded |
| C．damaged |
| D．destroyed |
________ caused the accident is still a complete mystery.
| A．What | B．That | C．How | D．Where |
I’m afraid he’s more of a talker than a doer，which is ________ he never finishes anything. (2011·山东，26)
| A．that | B．when |
| C．where | D．why |
Scientists study ________ human brains work to make computers. (2012·四川，17)
| A．when | B．how |
| C．that | D．whether |
It suddenly occurred to him________he had left his keys in the office. (2012·江西，25)
| A．whether | B．where |
| C．which | D．that |
Jerry did not regret giving the comment but felt ________ he could have expressed it differently. (2012·北京，24)
| A．why | B．how |
| C．that | D．whether |