His wife, to whom he_______ for 20 years , was childless.
| A．had married | B．married |
| C．has married | D．had been married |
—Some English idioms are difficult to understand.
—Exactly, ________ you know the meaning of each word.
| A．if only | B．even if | C．as if | D．now that |
. Whether ways will be found to stop pollution or not is just ______ worries the public.
| A．which | B．that | C．what | D．where |
What a pity! I _____ in London for three more days, but something urgent needed to be dealt with back in Beijing.
| A．must have stayed | B．could have stayed | C．may have stayed | D．needn’t have stayed |
．Canada, ________ second to Russia in size, is ________ home to all kinds of animals and plants, making it famous for its natural scenery.
| A．不填，a | B．the, the | C．the, 不填 | D．不填，不填 |
The trapped car could hardly make any advance and ________ could it draw back in the mud.
| A．neither | B．so | C．either | D．both |