Wemust ______ the time that you’ve wasted this afternoon by working lateto-night.

You can never imagine _______difficulty we had _______the cupboard upstairs.

Some people try to knock me down, only ________ me more determined to do better.[ ]

The college has developed an on-line system ________students can choose their own professors.

Smoking can help you relax. But _______ it is also bad for your health.