. Experts have warned ______ of the health risks caused by passive smoking.
| A．at a time | B．at one time | C．for some time | D．for the time |
In the dark forests ,some large enough to hold several towns.
| A．stand many lakes | B．lie many lakes | C．many lakes lie | D．many lakes stand |
—What are you mailing, Tom?
— A textbook a new method of teaching physics. I want my friends to take a look at it.
| A．is based on | B．based on | C．basing upon | D．which based upon |
She was about to leave the room the telephone rang.
| A．when | B．while | C．after | D．since |
I insisted that a doctor immediately.
| A．has been sent for | B．sends for | C．will be sent for | D．be sent for |
We all know it will be next June we can really have a rest.
| A．when | B．before | C．since | D．until |