— Perhaps we can go to the home for the elderly to do some voluntary work.

— ______ We should give the elderly a warm hand as often as possible.

A．I can’t agree more.

B．Do you think so?

C．Are you serious?

D．You must be joking!

凸缘式联轴器属于（）。

A、固定联轴器

B、可移式联轴器

C、安全联轴器

D、普通联轴器