滚动轴承内圈与轴的配合为基孔制配合，因此内圆的公差带位于零线的上方。
A. 对
B. 错
In what structures does gas exchange occur in the lung?
A. trachea
B. bronchioles
C. bronchi
D. alveoli
What is the name of the membrane that encloses the lung?
A. endothelium
B. septum
C. pleura
D. mucous membrane
Which of the following structures produces speech?
A. pharynx
B. larynx
C. trachea
D. pulmonary system
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