Eighty percent of the teachers ______ women teachers in our school.
| A．is | B．are | C．be | D．was |
______ he talked with her for a long time, he failed to convince(说服)her.
| A．Though | B．But | C．Since | D．As |
Take a map with you while traveling ________ you have a guide or know the city well．
| A．since | B．if | C．unless | D．because |
- The air pollution is terrible.
- It will be worse ________ we take action to protect the environment.
| A．if | B．unless | C．until | D．when |
She has worked in this factory ______ she came here in 2010.
| A． when | B． since | C．for | D．from |
-I’m afraid the meeting has begun. -Don’t worry. It ___ until the bell ____.
| A．doesn’t begin ;rings | B．won’t begin ; will ring |
| C．won’t begin ;rings | D．doesn’t begin ;will ring |