Economy of the world in 2010 was not so good. Many small companies ______.[ ]

A. closed up

B. drew up

C. picked up

D. grew up

旁气流通气监测法的缺点是（）

A.不能完全代替术前肺功能检查

B.不能测功能残气量和全肺容量

C.不能测吸（呼）气补量

D.不能测肺活量

E.以上均是