治疗变异型心绞痛疗效最好的是
A．β受体阻滞剂B．钙通道阻滞剂C．硝酸酯类D．ɑ受体阻滞剂E．血管紧张素转换酶抑制剂
参考答案：B
—Did you enjoy the book?
—Yes, it was so interesting that I could hardly_________it.
A．get rid of
B．break away from
C．keep away from
D．tear myself away from
已知电阻R1、R2串联在电路中，则电路的总电阻为（）。
A.R＝R1＝R2
B.R＝R1＋R2
C.R＝1／R1＋1／R2
D.R＝1／R1＝1／R2
