Expressing Duration With 多久

Whether you want to express how long you have studied Chinese, how long you are going to stay in China, or if I plan to work for this company for 5 years, you will need to use this grammar structure to express time duration. Saying how long you will do or did something for in Chinese can seem tricky, as there is no preposition similar to English. Instead it's all about the order of words.

As we know, a specific time should go before the verb. However, the duration of time goes after the verb.

Asking “how long” using question words：多久duōjiǔ，多长时间duōcháng shíjiān，几个月jǐgeyuè，几天jǐtiān, etc.

subject + specific time + verb + duration time/question word

A：Nǐ zuówǎn zàijiā shuìle jǐ gè xiǎoshí? ——>How many hours did you sleep at home last night?           你昨晚在家睡了几个小时？ B：Wǒ zuówǎn shuìle 10 gè xiǎoshí. ——>I slept 10 hours last night.      我昨晚睡了10个小时。

A：Nǐ míngnián huì zài zhōngguó gōngzuò duōjiǔ? ——> How long will you be working in China next year?      你明年会在中国工作多久？ B：Wǒ míngnián huì zài zhōngguó gōngzuò sān gè yuè. ——> I will work in China for three months next year.       我明年会在中国工作三个月。

A：Nǐ zuótiān yóuyǒng yóule duō cháng shíjiān?  ——> How long did you swim yesterday?         你昨天游泳游了多长时间？ B：Wǒ zuótiān yóule yīgè xiǎoshí. ——> I swam for an hour yesterday.     我昨天游了一个小时。

Note 1：In the first and second sentences, 了le is placed after the verb (to indicate that the action is completed), followed by the duration. This is how you talk about the duration of completed actions. However，会huì is placed before the verb, followed by the duration.

Note 2：Also in the first Chinese sentence, “觉jiào” can be omitted because “睡shuì” means to sleep, “觉jiào”  means a sleep. “睡shuì”  is clear enough to express the action of sleeping when it goes with a complement. But for most other VO structure words, which the "object" is not the only object for the noun, you need to keep the object.

Note 3：Why did we repeat the "游yóu" in the last example, I bet you wondered about that huh? Basically, duration time has to come RIGHT AFTER THE VERB. In this case,  "游yóu" is our verb and "泳yǒng" is the noun. There are many VO(verb-object) structure words in Chinese language and "游泳yóuyǒng" is one of them. By repeating the verb, we can have an object and a time duration in the same sentence!  If that doesn't make sense, just remember the formula, cause it's a simple rule: verb + obj + verb + duration time. Since the question is asking about the "action (游泳yóuyǒng)" in the past, we do need to put "了le" after the "verb", "游yóu". 

Note 4：When we answer this kind of questions or the context is clear, the object can be omitted. Like the fourth sentence, verb + duration time.

You can also make longer sentences by adding more elements.

Tā dǎsuàn zài běijīng zhù 3 nián yǐhòu, qù shànghǎi gōngzuò. ——> He plans to go to Shanghai to work after living in Beijing for three years. 他打算在北京住3年以后，去上海工作。

Xiànzài wǒ de yǎnjīng fēicháng lèi, yīnwèi wǒ kàndiànnǎo kànle yītiān . ——> Now my eyes are very tired because I watched the computer all day. 现在我的眼睛非常累，因为我看电脑看了一天。