精馏塔内气液都是饱和状态。()
参考答案:错
Most of today’s youngsters prefer to ______ to their favorite journals online because they think it is both trendy and handy.
A.contribute
B.resort
C.subscribe
D.relate
安装蒸汽喷射器时若受高度限制需水平放置时,吸入口必须()。
A.向上
B.向下
C.水平
D.与水平成30角