查询词典 have trouble doing sth.

Inform sb of the existence of (sth interesting or advantageous );tell sb about sth

向某人提供的信息；将某事物告诉某人

Inform sb of sth; report sth to sb.

通知某人某事，将某事报告某人

Tell sb. of sth. inform sb. of sth warn sb. of fire

4： of表示人物的特性，籍贯，特性或出生等

Notify sb. of sth.= inform sb. of sth.

正式通知、报告某人某事

Invite sb to do sth./be invited to do sth.

邀请某人做某事、被邀请做。。

They invited us to lunch. invite sb. to sth./ do sth.

邀请某人到某个地方或做某事

Invite sb. to sth./ invite sb. to do sth.

邀请某人到…/邀请某人做

It is a time for sth/to do sth.

该是……的时候了

Keep one's mind on sthbcontinue to pay attention to sth; not be distracted from sth

继续专心於某事物；不因某事物分散注意力

Keep sb/sth on phr v (=to continue to employ someone/rent sth, especially for longer than you had planned and)v.

继续雇佣，继续租用某物

In other research, chondroitin is being investigated for use in several other conditions.

在其它研究，软骨素被调查用於几个其它情况。

They would make fun of him for having to work.

他们拿他的工作来开玩笑。