It is usually cool in April in Chongqing, but it sometimes ______ be rather hot for a few days.
| A．can | B．must | C．shall | D．ought to |
The person we spoke to ____ no answer at first．
| A．making | B．makes | C．make | D．made |
You can never imagine what great difficulty I have _____ your house.
| A．found | B．finding | C．to find | D．for finding |
Before he went abroad, he spent as much time as he ____ English.
| A．could learning | B．learned | C．to learn | D．could learn |
Mr. Wang made up his mind to devote all he could ____ his oral English before going abroad.
| A．improve | B．to improve | C．improving | D．to improving |
It was quite a serious accident, _________ caused by careless driving.
| A．which I think was | B．I think which was |
| C．which I think it was | D．I think which it was |