（）是企业生产经营活动中可控制的因素，商品流通企业可以通过自身的努力加以调整和改善。

The nurse is caring for a client who is experiencing sinus bradycardia with a pulse rate of 40 beats/minute. His blood pressure is 80/50 mmHg and he complains of dizziness. Which medication would be used to treat his bradycardia

A. Atropine.
B. Dobutamine (Dobutrex).
C. Bretylium (Bretylol).
D. Lidocaine (Xylocaine).

A true gentleman is always _______ with himself and tolerant with others.

A．strict

B．cautious

C．enthusiastic

D．positive

有机物只含碳氢两种元素。

流水养鱼同池塘养鱼相比施药（）。

A、大

B、小

C、为零

D、不变

灭弧装置主要有那几种形式？