______ out for food. Some work in the tunnels as guards and workers.
| A．Not all the ants go |
| B．All the ants not go |
| C．Both the ants don’t go |
| D．All the ants go |
—Where is Tom ?
—Well , he __________ you __________ here. Otherwise he would come down right now.
| A．didn’t know ; were | B．hasn’t known ; are |
| C．doesn’t know ; are | D．hadn’t known ; were |
. All of the guests ___________ by 9 o’clock , but the host _____________ until 15 minutes later .
| A．arrived; didn’t turn up | B．had arrived; didn’t turn up |
| C．arrived; hadn’t turned up | D．had arrived; hadn’t turned up |
Mike didn’t notice Alice entering his room. He ____ a phone call.
| A．answered | B．has answered | C．was answering | D．is answering |
—Did you find the missing couple in the mountain yesterday?
—No, but we ________ to get in touch with them ever since.
| A．have tried | B．have been trying |
| C．had tried | D．had been trying |
—Such a mistake could have been avoided.
—Unfortunately, he _______ the mistake again and again.
| A．repeated | B．would repeat |
| C．had repeated | D．would have repeated |