用所给词的适当形式填空。

1. My hobby is reading comic books. What about _____ (you)?

2. Two _____ (five) of the students in our class are League members.

3. I don't think it's always right to be busy _____ (make) money all day.

4. He left home in a hurry because he had some problem _____ (solve) in his office.

5. I don't like travelling by plane. I think it's _____ (safe) to travel by train.

上述哪个镇痛药物含有1个手性碳原子，左旋体镇痛活性比右旋体大（）

A.吗啡

B.美沙酮

C.芬太尼

D.喷他佐辛

E.纳洛酮