下列物质露置在空气中一段时间后，质量不会发生变化的是（　　）

A．生石灰

B．氯化钠

C．浓硫酸

D．浓盐酸

In reviving a person who has been overcome by gas fumes，what would you AVOID doing?（）.

A.Giving stimulants

B.Prompt removal of the patient from the suffocating atmosphere

C.Applying artificial respiration and massage

D.Keeping the patient warm and comfortable