— Shall I go and buy two more bottles of beer?
— No, I’ve already bought twenty. That _____ be enough for us two.
| A．can | B．may | C．ought to | D．might |
______ it have been the failure to pick up directions from the ground control that caused the air crash?
| A．Must | B．Could | C．Would | D．Should |
The one concern for parents and students is _______ the student pursues their university education in a foreign country, the student will not have the opportunity to establish social contacts in China.
| A．that | B．that if | C．whether | D．how |
After the quarrel, I tried all my best to fix the misunderstanding between us, but all my efforts seemed _____.
| A．in trouble | B．in case | C．in effect | D．in vain |
Failure hurts grown-ups and children___________, but it can make a positive contribution to your life once you learn to use it.
| A．actively | B．likely | C．alike | D．similarly |
If the food tastes nice, I’ll go to buy some more; _______, I won’t go.
| A．if not | B．when not | C．if any | D．when ever |