Joe likes ______, but he doesn't like ______ this afternoon.

[      ]

A. skate; skating

B. skates; skating

C. skating; skating

D. skating; to skate

吸气性呼吸困难严重时可出现三凹征，其原因为：（）

A．喉与大气管狭窄或梗阻

B．小气管痉挛与狭窄

C．大片肺不张

D．大量胸腔积液

E．自发性气胸