.
Tom is reading a book __________ his brother is watching TV.
| A．while | B．though | C．however | D．but |
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 |
You all had a good time yesterday,________?
| A．hadn’t you | B．haven’t you | C．didn’t you | D．don’t you |
The Greens seldom go to the concert,________?
| A．don’t they | B．do they | C．don’t he | D．do he |
The shop doesn’t open until 11 a. m.,________ it loses a lot of business.
| A．for | B．or | C．but | D．so |