常用继电器按动作原理分为哪些类型?
参考答案:
电磁型、感应型、电动型、磁电型。
— What do you want to eat for lunch? I will prepare it earlier today.
— You_____, mum. Let’s go out to have something different.
A.mustn’t
B.can’t
C.shouldn’t
D.don’t have to
能快速控制和改善心绞痛发作的药物主要是
A.止痛剂
B.硝酸酯类
C.抗栓(凝)剂
D.血管紧张素Ⅱ受体阻断药
E.血管紧张素转换酶抑制剂