—There aren’t any toys in our suitcase．Where have you put them?
—Oh, no．That old lady sitting next to us ______ have taken ours by mistake.
| A．must | B．could | C．should | D．would |
—Jack can't concentrate on his lessons recently.
—Yes, that might ____ why he did so badly in the last test.
| A．answer for | B．apply for | C．call for | D．account for |
Theytwo free tickets to Australia, otherwise they’d never have been able to afford to go.
| A．had got | B．got | C．have got | D．get |
Not until they left school how much their teachers loved them and helped them.
| A．they realized | B．did they realize |
| C．had they realized | D．they would realize |
This new kind of chemicals will help keep the air, soil and water________ from pollution.
| A．free | B．empty | C．loose | D．short |
---I have cleaned the room three times a day. Look, It is a mess again.
---! Wait until the children go to bed.
| A．How come | B．Why bother | C．So what | D．What for |