--- ________ David be the new chairperson of the Students’ Union?--- He _______ be, but I’m not sure.
______ he talked with her for a long time, he failed to convince(说服)her.
Take a map with you while traveling ________ you have a guide or know the city well.
- The air pollution is terrible.- It will be worse ________ we take action to protect the environment.
She has worked in this factory ______ she came here in 2010.
-I’m afraid the meeting has begun. -Don’t worry. It ___ until the bell ____.