减压病是血液中哪种气体游离出造成的()
A.氧气
B.氢气
C.氮气
D.氦气
E.氖气
参考答案:C
Wood is often _________ paper.[ ]
A. used to making
B. used to make
C. used to be made
D. used making
巴西东海岸冬季盛行()。
A.西北风
B.西南风
C.东南风
D.东北风