慢性支气管炎时等压点由（）,以致在用力呼气时可使小气道闭合

I still remember __________ chess in clss by my techerbout twenty yersgo.to be cught to ply B．being cught plying C．ctching ply D．hving cught plyingA．to be caught to playB．being caught playingC．catching playD．having caught playing

Ⅰ、钢板
Ⅱ、型钢
Ⅲ、铸钢及锻钢
Ⅳ、一般强度结构钢
Ⅴ、高强度结构钢
A. Ⅳ、Ⅴ
B. Ⅰ、Ⅱ、Ⅲ
C. Ⅰ、Ⅱ、Ⅳ、Ⅴ
D. Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ