—What do you think makes him so sad?
— __________ the exam.
| A．He failed | B．He failing |
| C．His failing | D．To have failed |
.
___________ in the sports world, a sportsman needs to train constantly to keep himself in best condition.
| A．Survive | B．Surviving | C．To survive | D．Survived |
.
Listen, Mike. She ________________ have done it. She's been with me at the shop all day.
| A．couldn't | B．shouldn't | C．needn't | D．wouldn't |
.
—Do you want to go to the cinema tonight?
—Sorry, I’m so tired. I ___________ an early night.
| A．have | B．am having | C．have had | D．had |
.
With age, the mineral content of human bones decreases, ________ them more fragile.
| A．make | B．to make | C．made | D．making |
.
Let's go a little faster, ______________ we'll never get there on time.
| A．yet | B．or | C．so | D．and |