填空题。

     Keeping in touch with our friends is an important part of friendship. This does not mean that   1  have

to write or call our friends every day. It does mean, however, that we   2  care enough about our friends

to find out how they are doing from time to time.

     People have different habits about keeping in touch with others. Some like to call their friends,

sometimes many times   3  a day. Others prefer to e-mail their friends. Still   4    prefer writing letters so

that they can include photos or interesting articles  5  the envelopes along with their letters. Some even

write postcards while they are on vacation  6  send them to friends.

     Every kind of communication is important. It is   7  important what kind of call we make or letter we

send.   8  is important is that we let others know we care about them.

下列哪个属于预防偏头痛发作的药物（）

A.非甾体抗炎药

B.麦角类制剂

C.曲普坦类药物

D.阿片类药物

E.钙离子拮抗剂