介词 until (till) 与 by 的用法区别

介词 until (till) 与 by 的用法区别 

用作介词的 until（包括 till）和by，均可表示“在某时之前并不晚于某时的任何时间”，使用时注意以下几点：

1. until / till 通常只与表示一段时间的“持续动词”（如stay, wait）连用时。如：

She stayed until noon. 她呆到中午才走。

It may last till Friday. 这可能要延续到星期五。

I remain in London until May. 我在伦敦一直呆到五月。

We talked until midnight and then separated. 我们一直谈到深夜才分手。

It was his intent to leave at 6:30, but he stayed until 8:00. 他本打算六点半离开，但是他一直呆到八点。

We are counting down the days until the end of the exams. 我们倒数着日子，一直数到考试结束。

注：若所用动词只表示一时点（如finish, leave），则只能在否定句中用till / until。如：

You mustn’t open this parcel until Christmas Day. 圣诞节前你绝不能打开这个包裹。

We got home at 6 o’clock, but the other didn’t get back until 10. 我们6点钟到家，而另外几个l0点才回来。

He promised to be here at four o’clock but didn’t appear until six. 他答应四点钟来，可是六点钟才到。

I arrive at the hospital at eight o’clock, but I don’t go on duty until nine. 我八点钟就到医院了, 但是九点钟我才去值班。

Women were not given the franchise in Britain until the twentieth century. 英国妇女直到二十世纪才获得选举权。

2. 介词 by 通常只与表时点的动词连用。如：

She’ll have retired by then. 她到那时就要退休了。

We had hoped to finish by four o’clock. 我们原希望四点钟前能完成。

I’ll have left by Monday. (=any time before and not later than) 到星期一我就已离开了。(=在星期一前不晚于星期一的任何时间)

You’ll have to shift if you want to get there by nine o’clock. 你要想九点钟到那儿, 就得快点。

We’re in big trouble if we don’t come up with the money by 6 o’clock. 如果我们6点之前拿不出钱来，麻烦就大了。

注：有些表示状态的动词在某些特殊搭配或语境可以表示“时点”，则此时也可与 by 连用。如：

As a rule I’m home by six. 此句应理解为“我通常六点钟到家”（相当于As a rule I get home by six.），不能理解为“通常六点钟前我待在家里”。

She worked hard so that everything would be ready by 6 o’clock. 此句应理解为“她拼命干以便能到6点时把一切都准备好”（相当于She worked hard so that everything would get ready by 6 o’clock.），不能理解为“她拼命干以便能到6点时一切都一直是准备好的”。

其他例句如(www.hxen.net)：

We shall be back by six o’clock. 我们六点钟回来。

The children must be back by 4 o’clock. 孩子必须4点钟以前回来。

I drove home to him that he must be here by ten. 我跟他说得清清楚楚：他必须十点钟以前到这里。

3. 当与表时点的动词连用且用于否定句时，两者都可以用。如：

I won’t have left by Monday. (=I’ll still be here on Monday) 我星期一前不会离开的。(=我星期一还在这儿)

We got home at 6 o’clock, but the others didn’t get back until 10. 我们6点钟到家，而另外几个l0点才回来。

Might I enquire why you have not mentioned this until now? 请问你为什么直到现在才提及此事呢？