now在句中除作状语外,还可作主语、表语或介词宾语。

(every) now and again〔then〕
时而,偶尔,有时at irregular intervals; occasionally
She meets her old boyfriend for a drink now and again.她不时与她过去的男朋友见面去喝上一杯。
I like to go to the cinema now and then.我喜欢偶尔去看电影。
I see him every now and then, but not often.我偶尔看见他,但不经常看见他。

now for sth
用以转折,以提出新任务〔新话题〕used when turning to a fresh task or subject
Now for the next question.现在谈下一个问题。
I think we've finished with that point.Now for the next item on the agenda.我想那个问题我们已讨论完了,现在就来研究日程上的下一个项目吧。

now, now
用于表示不赞成〔劝慰〕的话语之前used before expressing disapproval or admonishment
Now, now,Harriet!It's all right!There's no need to cry!好啦,好啦,哈利特!沒有关系!没有必要哭呀!

now...now〔then〕
时而…时而…at one time...at another time
His moods kept changing—now happy, now filled with despair.他情绪多变——时而高兴,时而感到绝望。
Now we could see him, then he disappeared behind a tree.忽而我们能看见他,忽而他躲在一棵树后不见了。

now then
1.用于表示不赞成〔劝慰〕的话语之前used before expressing disapproval or admonishment
Now then, that's enough noise.行了,别吵了。
Now then, don't worry about it.好啦,别为这件事担心。
2.用以引出要说的话,以提出建议〔征询回应〕used to introduce a statement that makes a suggestion or invites a response
Now then, what did you want to tell me?那么,你想告诉我什么吗?
3.考虑下一步要做的事或要说话时,用来填补暂时的停顿used to fill a pause when one is thinking what to do or say next
I must say I enjoyed that.Now then, what's next?我的确很喜欢这个。那么,下一个呢?

I had a headache this morning, but I'm all right now.我今天早上头疼,但现在好了。
Where are you living now?你现在住哪儿?
Now is the best time to play basketball.现在是最适合打篮球的时候。
Start writing now.立刻开始写。
You've got to ask him.It's now or never.你得去问他,机会难得。
Until now she has never been to see a doctor.到目前为止她还没有去看过医生。
He ought to be in London by now.此刻他应该在伦敦了。
Now the next thing he did was to light a cigarette.然后他点了一支烟。
Now be quiet for a few moments and listen to this.请安静一会儿,注意听着。
No cheating, now.不许作弊。

now that可用作连词,作“由于…; 既然…”解, that可省略。例如:
Now that you're grown up, you must stop this childish behavior.你既然长大了,你就必须去掉这种孩子式的举动。
Now (that) John's arrived, we can begin.既然约翰来了,我们就可以开始了。

［词源］＜古英语nu(现在,如今)