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