Hard _____ he tried, he failed to catch up with the first runner.
| A．although | B．as | C．while | D．when |
Young people seem to have no time to spend with other people around them ______ giving so much attention to their own world.
| A．in spite of | B．regardless of | C．due to | D．according to |
One of the requirements for the experiment is that the material _____ to its burning temperature．
| A．is heated | B．will be heated | C．be heated | D．would be heated |
---- Occasions are rare _____ I can spend a day with my daughter.
---- You should spare some time to accompany her.
| A．when | B．where | C．which | D．that |
I will never understand how it ______ that you failed in the examination for you are such a good student.
| A．came about | B．brought in | C．stayed up | D．ended up |
----Do you have any idea why Mark is leaving?
---- No. In fact, everyone is ________about it．
| A．doubtful | B．curious | C．enthusiastic | D．annoyed |