Every possible means ______, but none proves successful.
| A．has tried | B．have been tried |
| C．is being tried | D．has been tried |
.If the firms failed to make enough money, they would __________.
| A．close down | B．call off | C．turn down | D．set off |
.Emergency line operators must always ______ calm and make sure that they get all the information they need to send help.
| A．grow | B．appear | C．become | D．stay |
The news of the mayor’s coming to our school for a visit was __ on the radio yesterday.
| A．turned out | B．found out | C．given out | D．carried out |
.I have ______ all my papers but I still can’t find my notes.
| A．looked through | B．looked for | C．looked after | D．looked out |
She’s having a lot of trouble with the new computer, but she doesn’t know whom to ____.
| A．turn to | B．look for | C．deal with | D．talk about |