He liked to go to dances and parties, he could have a good time just sitting and watching.
| A．where | B．when | C．which | D．that |
If human beings had been a bit less greedy and cruel, more birds and animals _______dying out.
| A．ought to avoid | B．could have been avoided |
| C．should have avoided | D．might have avoided |
With a lot of difficult problems____________, the manager felt worried all the time.
| A．to settle | B．settling |
| C．settled | D．being settled |
--Was Tom there when you arrived?
--Yes, but he___________ home soon afterwards.
| A．had gone | B．has gone | C．is | D．went |
—Look at these tracks. It __________ be a wolf.
—It needn't be. It ___________ be a fox.
| A．must; could | B．may; might |
| C．need; must | D．could; need |
Travelers_______________ that they should bring their ID cards with them.
| A．have reminded | B．are reminded |
| C．were reminding | D．had been reminded |