功能镇惊安神，平肝潜阳，聪耳明目，纳气平喘的药物是（）。
A.龙骨
B.磁石
C.琥珀
D.牡蛎
E.朱砂
参考答案：B
Swimming in the pool with friends _________ very interesting. [ ]
A. has
B. have
C. is
D. are
低压带电作业应遵循的原则是什么？
