A:实践具有社会历史性特征
B:人民群众是历史的创造者
C:质变是量变的必然结果
D:整体与部分是相互联结的
一元二次方程x2﹣2x=0的根是( )
(1 )已知液态氧和液态氮的沸点分别是﹣183℃和﹣195.8℃.要从空气中获取氧气,可根据液态氧和液态氮的沸点不同,采用蒸馏液态空气的方法.
(2 )实验室用蒸馏的方法制取蒸馏水
(3 )海盐厂以海水为原料,用太阳能蒸发法晒得粗盐.
给下列句子选择合适的答语。
① How do you like this chess? ____ A. It's$50.
② How much is this sweater?____ B. Yes How much is it?
③ The socks are $50. ____ C. It's very pretty.
④ Can l help you? ____ D. They're too expensive.