________that you come here earlier tomorrow or you'll be in trouble.
| A．Be sure of | B．Make sure |
| C．It's sure | D．Make sure of |
.
. All books ___________ to the library more than three days late will be subject to a fine.
| A．return | B．returning | C．to return | D．returned |
.
When he was only thirty years old, he had already experienced ___________ most people only experience when they are much older.
| A．what | B．which | C．who | D．when |
.
___________ 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 |