动式染毒主要优点是()。
A.装置备有新鲜空气补充
B.受试化合物保持浓度不变
C.保证染毒柜内和二氧化碳分压恒定
D.温湿度恒定
E.以上都是
参考答案:E
—Jenny hasn't paid for her leather jacket, has she?
—_____. Her cousin will pay for her. [ ]
A. Yes, she has.
B. No, she hasn't.
C. Yes, she did.
D. No, she didn't.
假定某公司普通股股票当期市场价格为15元,那么该公司转换比率为30的可转换债券的转换价值为( )元。
A.0.5 B.2 C.30 D.450