How to express obligations in Mandarin Chinese?

To express obligations in Mandarin Chinese, you can use obligation words like
一定 (yīdìng, must), 得 (děi, should), 不许 (bùxǔ, must not/not allowed), and 不要 (bùyào, should not). In Mandarin, you’ll use obligation words to express social and moral obligations. For example:

There are some interesting things about obligation words in Mandarin. For example, some words convey a stronger sense of obligation than others. The Chinese use 一定 (yīdìng, must) to express a strong sense of obligation and 得 (děi, should) for a weak sense of obligation.
不许 (bùxǔ, must not/not allowed) and 不要 (bùyào, should not) are used to express negative obligations, something you must not or should not do or say.

Read on to learn more about how these obligation words are used and you’ll be able to express obligations accurately in Mandarin!

The following words express strong obligations in Mandarin Chinese, showing the determination of the speaker themselves or the addressee. That is, these words recommend people do something, and they must do it. These words also convey the message that if things don’t get done, then serious consequences may occur.

These strong obligation words are often used in formal contexts. However, they may also be used in informal contexts. For example, if a mother tells her daughter not to go out after dark, the daughter may say,

Here, “must” is used in informal conversation.

The word 要 (yào, want) can be added to most of the strong obligation words above to enhance the strength of the obligation. For example, we can say, 我们必须要这么做 (Wǒmen bìxū yào zhème zuò, We must do it). The only exception is that 要 (yào, want) cannot be added to 不得不 (bùdébù, have to).

The word 会 (huì, will) can be added only to 一定 (yīdìng, must) to enhance the strength of obligation. For example:

The following words can be used to express weak obligations in Mandarin Chinese:

This group of obligation words is soft and less strong than those of the previous group. For example, 得 (děi, “have to”) in this group conveys a weaker sense of obligation than 必须 (bìxū, “must”) in the previous group. The former is usually used in informal and spoken contexts, as opposed to the latter in formal and written contexts.

Instead of 应该 (yīnggāi, should), you can also use 应 (yīng), 该 (gāi),
应当 (yīngdāng), and 当 (dāng).

The first four are interchangeable. For example, we can say,

On the other hand, 当 tends to be used in Chinese poems, old sayings, etc. For example, 男儿当自强 (Nán'ér dāng zìqiáng, A man should stand strong) is a Chinese saying. This saying always refers to male addressees, telling them that men must be strong whatever the difficulties.

最好 (zuìhǎo, had better) can be used to either lay an obligation or make a covert threat. For example:

vs.

These are the commonly used negative obligation words in Mandarin Chinese, compared to the positive ones:

The negative form of the majority of obligation words is 不必 (bùbì) or 不用 (búyòng), which is equivalent to the English “don’t have to.” For example, the negation of 他得去 (Tā děi qù, He has to go) is 他不用去 (Tā bùyòng qù, He doesn't have to go).

Most positive obligation words can be replaced with 不必  (bùbì) or 不用 (búyòng) for their negative forms, but there are some negative obligation words that are made by adding 不 (bù) to their positive forms. For example, 一定不 (yīdìng bù) matches 一定 (yīdìng), 不应该 (bù yīnggāi) matches 应该 (yīnggāi), and 不要 (bùyào)/不需要 (bùxūyào) matches 要 (yào) / 需要 (xūyào). For example:

In Mandarin, obligations may be expressed strongly (e.g.,
一定) or less strongly (e.g., 得). There are also negative forms of obligation words. The table below summarizes all three types of obligation words:

Now it is time to put your knowledge of obligation words into practice. These exercises will help you to practice how to use obligation words in Mandarin Chinese correctly, so go ahead and check them out.