我已咨询过关于空运送货。它快捷，货物不如海运那么容易受损。而且受耽搁的风险也较小。

Sentence No. 1 Courses for adult students may be vocational or recreational, that is, they may be related to a person’s job or taken purely for interest and pleasure.

Sentence No. 4 I’ve been looking into the question of having the goods sent by air. It’s quick, the good are less liable to damage than by sea, and there’s less risk of hold-ups.