How to express sentences containing length of time

To express that an action was carried out over a certain length of time, English uses often "for". This is a very versatile word in English, so there a few different points to consider when expressing the same thing in Mandarin. 

在英语中，表达某个动词持续了某段时间时用“for”。“for”的用法很多。在此，我们要介绍带有“for”的句子用中文是如何表达的。

The basics:

基本用法：

In most cases the length of time is added right after the verb. Simple as that. Some examples:

在大部分情况下，“时间段”应紧靠动词之后。用法非常简单。例句：

鸡蛋至少要煮5分钟。 

Jīdàn zhìshǎo yào zhǔ 5 fēnzhōng. 

Eggs should be boiled for at least five minutes.

我们可能去旅行几天。 

Wǒmen kěnéng qù lǚxíng jǐ tiān. 

We could go travelling for a few days.

你最好低调几个星期。 

nǐ zuì hǎo dī diào jǐ gè xīng qī. 

You'd better lie low for a few weeks.

You don't need to add anything else in to mark the length of time. Just placing it after the verb expresses that the verb takes place for that length of time.

“时间段”无需任何词修饰，只需将其置于动词后面即可，表示动作在“时间段”内一直继续。

Including an object

带有宾语

The sentences above don't include an object. If there is one, the length of time goes after this. This is because the object is actually part of the verb phrase.

以上例句都没有宾语。如果句中有宾语的话，“时间段”应置于宾语之后，因为宾语本身就是动词短语的一部分。

Some examples:

例句：

你可以帮我十分钟吗？ 

Nǐ kěyǐ bāng wǒ shí fēnzhōng ma? 

Could you help me for ten minutes?

他可以借我的摩托车几天。

Tā kěyǐ jí wǒ de mótuō chē jǐ tiān. 

He can borrow my moped for a few days.

警察会追捕她很长时间。 

Jǐngchá huì zhuībǔ tā hěn cháng shíjiān. 

The police will pursue her for a long time.

Note that for separable verbs, the time can also be inserted in the middle of the verb. A couple of examples:

注意，若句中动词为离合动词，则“时间段”可置于离合动词之间，例句：

她每天上几个小时网。

Tā měitiān shàng jǐ gè xiǎoshí wǎng. 

She goes online for several hours every day.

你应该每天睡八个小时觉。

Nǐ yīnggāi měi tiān shuì bā gè xiǎoshí jiào. 

You should sleep for eight hours a day.

Length of time at the beginning

“时间段”在句首

Sometimes it's better to put the length of time near the beginning of the sentence. This happens when a verb phrase is used as the subject of the sentence.

动词短语作主语时，“时间段”应靠近句首。

Some examples:

例句：

等太长时间让大部分人觉得心烦。

Děng tài cháng shíjiān ràng dà bùfèn rén jué dé xīnfán. 

Waiting for too long makes most people annoyed.

一整个月没看到他们让我感觉很_难过。 

Yī zhěnggè yuè méi kàn dào tāmen ràng wǒ gǎnjué hěn nánguò. 

Not seeing them for a whole month makes me sad.

戒酒一年对身体好。 

Jiè jiǔ yī nián duì shēntǐ hǎo. 

Giving up drinking for a year is healthy.

Notice how this is often handled with -ing verbs in English. If a sentence starts with an -ing verb in English, chances are the duration needs to go near the beginning when translating into Chinese.

注意例句中是如何处理动词ing形式的。如果英文句子句首为动词ing形式，那么翻译成中文时，表示“时间段”的词语应尽量靠近句首。

What about 了?

句中含有“了”字

You might have noticed that the example sentences above all talked about hypothetical or habitual actions.

看了以上例句之后，你会发现，以上例句都是描述假设性动作或习惯性动作。

The example sentences above don’t need 了 as they don't specify whether or not the action is completed in the time frame we're talking about. If time frames are involved, you can be sure that the aspect particle 了 is going to rear its ugly head.

由于这些例句并没有指明某个动作是否在某个具体的时间内已经完成，因此无需加“了”。

Simply put, 了 is used to mark actions that are complete in the time frame we're talking about. The above sentences don't need 了 as they talk about uncompleted actions. Now it's time to start looking at some time duration sentences that do need 了.

简单地说，“了”表示在所描述的时间内动作已经完成。以上例句没有用“了”是因为那些动作都还没有完成。以下将介绍含有“了”且包含“时间段”的句子。

One 了

一个“了”

Putting 了 after a verb indicates that the action of that verb is completed in the time frame we're talking about. With duration, 了 indicates that the verb has been carried out for that length of time.

动词后面加“了”表明在所描述的时间内动作已经完成。若句中有“某个时间段”，“了”则是表示某个动作持续了“那段时间”。

Some examples:

例句：

我昨天看了两个小时电视。 

Wǒ zuótiān kànle liǎng gè xiǎoshí diànshì. 

I watched TV for two hours yesterday.

你到了以后等一会儿。 

Nǐ dàole yǐhòu děng yīhuǐr. 

When you get there, wait for a while.

我休息了一会儿再出去。 

Wǒ xiūxíle yīhuǐ'er zài chūqù.

I'll go out after I've rested for a while.

我昨晚睡了八个小时觉。 

wǒ zuó wǎn shuìle bā gè xiǎoshí jiào. 

I slept for eight hours last night.

Two 了

两个“了”

As well as the 了 that marks completeness, there is another kind of 了. This is often called sentence 了. Sentence 了 is used to indicate a new state or new situation.

“了”字除了可以表示动作完成之外，还可以用在句末或句中停顿的地方，表示出现新的情况或状态。

When aspect 了 and sentence 了 are used together, it expresses the sense of "this is how things are up to now". In English this is often expressed with "have" plus the past tense form of the verb.

表示时态的“了”和表示“新状态、新情况”的“了”在同一个句中出现，表示“到现在为止情况如何”。在英文中，这种句子通常会用“have”以及动词的过去分词表示。

Combining both kinds of 了 with a duration expresses that an action has been performed for that length of time so far. It implies that the action is going to continue in duration.

一个句子中包含两个“了”，且还有表示“时间段”的词语，则表明在这个“时间段”，某个动作已经完成，并暗含这个动作还将继续进行。

Some examples:

例句：

我们已经等了好几个小时了。 

Wǒmen yǐjīng děngle hǎojǐ gè xiǎoshí le. 

We've been waiting for hours.

那部电影他们看了半天了。 

nà bù diànyǐng tāmen kànle bàntiān le. 

They've been watching that film for ages.

Negative sentences with duration and 了

包含“时间段”和“了”的否定句

After all that, it might seem strange to talk about negative 了 sentences. If 了marks completed actions, surely a negative (and so uncompleted) action wouldn't need 了?

看了以上用法，再介绍包含“了”的否定句可能会令你困惑不解。如果“了”表示某个动作完成的话，那么否定句（动作没有完成）肯定就不需要加“了”了？

That is true for aspect particle 了, but not for sentence 了. Sentence 了 can mark that something has not been the case for an amount of time. This is a bit like saying "it's now the case that [not x] for [amount of time]".

但是，这种情况只适用于时态助动词“了”，而不是置于句中或句末的“了”。置于句中或句末的“了”表示某个动作或状态持续了某一段时间，有一点像英文中的“It's now the case that [not x] for [amount of time]”

Some examples：

例句：

我好多天沒吃东西了。 

Wǒ hǎoduō tiān méi chī dōngxile. 

I haven't eaten for days.

他们已经四十八个小时没_睡觉了。

Tāmen yǐjīng sìshíbā gè xiǎoshí méi shuìjiàole. 

They haven't slept for forty-eight hours.

我们已经十多年没见过他了。 

Wǒmen yǐjīng shí duōnián méi jiàn guò tāle. 

We haven't seen him for over ten years.

Translated from eastasiastudent.net