普萘洛尔阻断突触前膜上的β受体，可引起（）。

A.去甲肾上腺素释放减少

B.去甲肾上腺素释放增加

C.去甲肾上腺素释放无变化

D.心率增加

E.外周血管收缩

根据句意，用括号内所给单词的正确形式填空。

1. 一I _________ (have) lunch when Bill knocked at the door.

2. He used to enjoy _________ (listen) to rock music.

3. Chinese tigers live in the south of China. They aye the _________ (old) typle of tigers living in the world.

4. The rainforests can give us a lot of _________ (use) things.

5.一Would you mind _________ (teach) me? 一Not at all.