Flying kites, ______ some researchers point out, can not only bring about joy to us, but also promote our physical and mental health.
| A．which | B．what | C．as | D．where |
The driver ____ have drunk a lot before the accident, but I'm not quite sure of that．
| A．might | B．must | C．should | D．would |
When ____ to compare the education system of China and Britain, the professor gave no answer．
| A．ask | B．asking | C．asked | D．to ask |
Why not get some work experience first ______ go straight on to university?
| A．other than | B．rather than | C．more than | D．less than |
What if we meet with a situation _______ none of us are able to deal with?
| A．where | B．in which | C．what | D．that |
His lack of professional knowledge _______for the failure of the experiment.
| A．accounted | B．explained | C．counted | D．contributed |