用所给词的适当形式填空。

1. I used to _____ (live) in an apartment near Beihai Park.

2. Was Tom used to _____ (live) with his grandparents?

3. They became good friends when they met for the _____ (one) time.

4. In that school students have pretty _____ (relax) rules,

5. We never visit a friend's house without _____ (call) first.

降压至70%—80%运行时，触发角约为（）。

A.20°—30°

B.30°—40°

C.40°—50°

D.50°—60°