David is such a good boy _______ all the teachers like.
| A．that | B．who | C．as | D．whom |
—Show me your permit, please.
—Oh, it's not in my pocket. It ________.
| A．must have fallen out | B．might fall out |
| C．could fall out | D．should have fallen out |
People love the convenience of bottled water, but if they ________ the problem it causes, they ________ try carrying water in a reusable steel container instead of plastic.
| A．realized; will | B．had realized; will |
| C．realized; would | D．have realized; would |
If you want somebody to go window shopping with you, why not try calling Marie? —she ________ be home by now.
| A．shall | B．should |
| C．will | D．would |
—How was your trip to Yancheng last week?
—Wonderful! I only felt sorry that I ________ the nature reserve of redcrowned cranes, but the weather was awful.
| A．could visit | B．could have visited |
| C．might visit | D．might have visited |
If I ________ your advice then, I think that the crops could be growing better.
| A．took | B．would have taken |
| C．had taken | D．have taken |