The mother often tells her son to be a good boy, warning him to _____ trouble.
| A．keep out of | B．hold back from |
| C．break away from | D．keep up with |
More than a dozen students in that school _______ abroad to study medicine last year.
| A．sent | B．were sent |
| C．had sent | D．had been sent |
—Your job _______ open for your return.
—Thanks.
| A．will be kept | B．will keep |
| C．had kept | D．had been kept |
The discussion _______ alive when an interesting topic was brought in.
| A．was coming | B．had come |
| C．has come | D．came |
Because the shop _______, all the T-shirts are sold at half price.
| A．has closed down | B．closed down |
| C．is closing down | D．had closed down |
—I’m sorry,but there’s no smoking on this flight.
—Oh,I _______ that.Sorry, I won’t again.
| A．don’t know | B．didn’t know |
| C．won’t know | D．haven’t known |