- 得(děi, have to)
- 必须 (bìxū, must)
- 不用（bú yòng, don’t have to）
- 应该 (yīng gāi, should)
The differences between 得、必须 and 应该
得 (děi, have to) and 必须 (bìxū, must) both express obligation, and 得 (děi, have to)means a less strong obligation than 必须(bìxū, must).
得 (děi, have to) definitely necessary in order to do something. If not done, one is unable to do something.
Eg:
1、你发烧了，得去看医生。（Nǐ fāshāole, nǐ děi qù kàn yīshēng. you had a fever, you have to see doctor.）
2、我得赶快出发, 否则就迟到了。（Wǒ děi gǎnkuài chūfā, fǒuzé jiù chídàole. I have to set out in a hurry, otherwise I will be late.）
whereas 必须 (bìxū) would be equivalent to English must, is very sure, if you don’t do something that will cause serious consequences.
Eg.
你出国之前必须先办理签证手续。(Nǐ chū guó zhīqián bìxū xiān bànlǐ qiānzhèng shǒuxù. Before going aboard you must first obtain a visa. )
So 得 (děi, have to) and 必须 (bìxū,must) share the same mean. “必须 “is more formal than”得“. “得” Somewhat similar to 必须(bìxū, must) but much more colloquial. Actually “得” is a dialect in north China, it is often used in daily life and is not used in formal writing.
The negative form of必须 and 得 is不用(bú yòng), which would be equivalent to English don’t have to.
Yes, you can use 不必(bú bì, not necessary) too.不用 = 不必
Eg.
1、我明天不用早起（Wǒ míngtiān bú yòng zǎoqǐ, I don’t have to get up early tomorrow.）
2、我可以自己从机场回家,你不必来接我.( Wǒ kěyǐ zìjǐ cóng jīchǎng huí jiā, nǐ bú bì lái jiē wǒ, It’s not necessary to pick me, I can go home alone from the airport.)
“得” can also means “需要” (xūyào, need)
Eg.
这辆车得多少钱?( Zhè liàng chē de duōshǎo qián? how much money needed to buy this car? )
In this sentence, you cannot use “必须” instead of “得”.
应该(yīng gāi) expresses necessity is similar to English should,
Eg.
我们应该(yīng gāi, should) 帮助穷人（we should help the poor.）
The negative form of 应该 is 不应该(bù yīng gāi, shouldn’t)
Eg.
他不应该对妈妈那样说话。（Tā bù yīng gāi duì māma nàyàng shuōhuà. He shouldn’t talk to his mother like that.）
First of all, thanks for posting this article, and all the other ones that I’ve come across.
With regards to this page: I get the idea, but I find your explanations too long, and examples not always the best: “whereas 必须 (bìxū) would be equivalent to English must, is very sure, if you don’t do something that will cause serious consequences.” is not a good explanation to explain the difference from 得. Also, 一定要 is missing form this series of expressions relation to ‘(not) must/have to’.
More in general, I find these explanations often quite elaborate, they could (and should) be much more consise, to the point. The articles can much shorter, which makes them more clear and improves learning. I take notes and rework/merge various sources of information. This is when I realise that often there is so much (confusing) redundance in the sources.
More than once I have found mistakes on your pages (sorry, I don’t recall them all), but here’s one:
出国 = going abroad (not: going aboard)
You may argue it’s only a small mistake, but on a website that is trying to teach a language, such mistakes should have been taken out in a review process. When I find such mistakes I start to wonder the validity of the rest of the information.
Please don’t get me wrong: I am grateful for the work you’re posting, and if I send you my feedback it’s only because I see an opportunity to make the content on your pages even better.
Dear L. van Groningen,
Thank you for your comment. We really appreciate the feedback like this.
We explained the words very elaborate because there were many learners who were still at a relatively low level and we were worried about if they could understand the content or not. That`s why we gave each of the explanation of the words and following several examples. But you are right, we should make both long and concise versions in the article to adapt to different audiences.
Regarding the typos you mentioned, we are really sorry about it. Most of the editors are Chinese whose English may not as good as the native English speakers. The typos are the one we always try to avoid. But sometimes it still happens… Anyway, we will try and work harder on it. Luckily, we have the audiences like you who often give us feedback to make the website better. Thank you again!