A：肺和气囊都能进行气体交换
B：只在吸气时，肺内进行气体交换
C：只在呼气时，肺内进行气体交换
D：吸气和呼气时，肺内都能进行气体交换
Fire can____ down a lot of trees. It can____ people, too. We must be____with fire. We mustn't____ in the forest. We mustn't play____ fires at home. We mustn't play with matches either.
下列哪项与小肠的吸收功能无关（ ）
414-238=
