If we throw away too much waste and can’t keep good ecosystem,we _________ our future.
| A．must have destroyed | B．could be destroying |
| C．may be destroying | D．must destroy |
Nobody phoned while I was out,________?
| A．did they | B．didn’t they | C．did he? | D．didn’t he |
Everything is ready,________?
| A．aren’t they | B．isn’t it? | C．isn’t everything | D．are they |
I don’t think Mary is angry with you,________?
| A．do I | B．is she? | C．isn’t she | D．don’t I |
I suppose he ought to have known that,________?
| A．don’t I | B．oughtn’t he | C．do I | D．ought he |
You’d never heard of it before I told you,________?
| A．did you | B．didn’t you | C．would you | D．had you |