Last term our maths teacher set so difficult an examination problem _____ none of us worked it out.
| A．that | B．as | C．so that | D．which |
The open-air celebration has been put off _______ the bad weather.
| A．in case of | B．in spite of | C．instead of | D．because of |
Many of them turn a deaf ear to his advice, _____ they knew it to be valuable.
| A．as if | B．now that | C．even though | D．so that |
I’d like to study law at university __________ my cousin prefers geography.
| A．though | B．as | C．while | D．for |
Some students often listen to music _____ classes to refresh themselves.
| A．between | B．among | C．over | D．during |
.—____ when has the country been open to international trade?
—1978, I suppose.
| A．Since | B．In | C．From | D．After |