具有开窍、辟秽、止痛之功，用治冠心病心绞痛的首选药物是()
A.石菖蒲
B.冰片
C.苏合香
D.丹参
参考答案：C
According to the rules of Daddy, where are we going?, nobody _______ take along with them cash and cell phones.
A．must
B．may
C．will
D．shall
三相异步电动机的制动方法有哪几种？
