在交流220V的电路上接一个开关和一个100W的灯泡,画出其电路图。
参考答案:
药物的特异性作用机制不包括()
A.激动或拮抗受体
B.影响离子通道
C.改变细胞周围环境的理化性质
D.影响自身活性物质
E.影响神经递质或激素分泌
A bond is needed when the bill of lading cannot be availed of the time of entry of the im- ported commodities. What does the sentence mean.()
A. A bond is needed when the bill of lading is unavailable when the goods arrive at the destination.
B. A bond is needed when the bill of lading arrives at the port of destination.
C. A bond is not needed when the goods arrive at the destination.
D. A bond is needed when the goods arrive at the destination if there is no bill of lading at all.