单选题 Which phrase is used to describe the volume of air inspired and expired with a normal breath?
A. Total lung capacity.
B. Forced vital capacity.
C. Tidal volume.
D. Residual volume.

【正确答案】 C
【答案解析】Tidal volume refers to the volume of air inspired and expired with a normal breath. Total lung capacity is the maximal amount of air the lungs and respiratory passages can hold after a forced inspiration. Forced vital capacity is vital capacity performed with a maximally forced expiration. Residual volume is the maximal amount of air left in the lung after a maximal expiration.