完形填空。
从A、B、C三个选项中选出可以填入空白处的最佳选项。
You may have headaches sometimes. But how much do you know          headaches? What may cause them? And what         we do if we have a headache? When should we go to see a       ?
A headache is not a disease, but it may show that there is        wrong with our body. Usually a cold or some           illnesses may cause headaches. We may have a headache when we work too      . We may get a headache      we don’t get enough sleep. When we have a headache, we should    and rest. We should have a good sleep. We      take too much exercise if we don’t feel well. If we have headache very    , we had better see a doctor.
A. with B. at C. about
A. should B. have C. must
A. doctor B. teacher C. movie
A. nothing B. anything C. something
A. other B. others C. another
A. easily B. hard C. early
A. so B. but C. when
A. do exercise B. fall down C. lie down
A. should B. shouldn’t C need
A. never B. always C. often