It _____ hard outside. You have to stay at home. [ ]
A. rain
B. is raining
C. rained
答案:B
根据国内外市场发展的态势,新产品的发展趋势表现在以下几个方面:().
A.多能化;
B.多样化;
C.微型化;
D.绿色化;
E.健美化、舒适化。
血清镁离子浓度达到多少可出现呼吸抑制()
A.0.75~1mmol/L
B.1.7-~3mmol/L
C.3.5~5mmol/L
D.>5mmol/L
E.>6mmol/L