查询词典 had better do sth.

It's time for sth./ for sb. to do sth.

是做…的时间了。

See sb. do sth./doing sth.

看见某人做某事/正在做某事

See sb./sth. do sth.

看见某人/物做某事。

See sb. doing sth. see sb. to do sth.

看见某人做某事

See sb. do sth./ see sb. doing sth

前者表示"看见某人做了某事"

Welcome to my blog !see sb. do sth./ see sb. doing sth

"see sb do sth "表示看到某人做某事了，强调看见谁做过什么事。

Do sth./ see sb. doing sth.

看见某人做某事/看见某人正在做某事

See sb.do sth./see sb. doing sth.

看见某人做某事/看见某人正在做某事

Send for sth./ send for sb. to do sth.

要求将某物取来或送到；请---来

Set out to do sth., set about doing sth.

开始做，着手做

Liapunov—Schmidt method is one of the most important method in the bifurcation theory.

Liapunov—Schmidt方法是分叉理论的最重要方法之一。

Be courteous -- even when people are most discourteous to you .

要有礼貌──即使当別人对你最不礼貌的时候。