Usage note
必要表示有需要、很重要。
bì yào biǎo shì yǒu xū yào 、 hěn zhòng yào。
必要 means necessary or needed.
Context note
必要常用于判断、建议和安排。
bì yào cháng yòng yú pàn duàn 、 jiàn yì hé ān pái。
It is often used for judgment, advice, and arrangements.
5 examples
有必要再检查一次。
yǒu bì yào zài jiǎn chá yí cì。
It is necessary to check once more.
这件事很必要。
zhè jiàn shì hěn bì yào。
This matter is very necessary.
必要时请联系我。
bì yào shí qǐng lián xì wǒ。
Please contact me if necessary.
没有必要担心。
méi yǒu bì yào dān xīn。
There is no need to worry.
必要的准备不能少。
bì yào de zhǔn bèi bù néng shǎo。
Necessary preparation cannot be missing.
5 mini stories
老师说必要的时候可以请假。
lǎo shī shuō bì yào de shí hòu kě yǐ qǐng jià。
The teacher said you can take leave when necessary.
他觉得这个说明很必要。
tā jué de zhè ge shuō míng hěn bì yào。
He thought this explanation was very necessary.
必要时，大家一起帮忙。
bì yào shí， dà jiā yì qǐ bāng máng。
When necessary, everyone helps together.
必要的步骤要认真完成。
bì yào de bù zhòu yào rèn zhēn wán chéng。
Necessary steps should be completed carefully.
这不是必要的改变。
zhè bú shì bì yào de gǎi biàn。
This is not a necessary change.
Mini dialogue
出门前
A
外面冷，有必要穿外套吗？
Wàimiàn lěng, yǒu bìyào chuān wàitào ma?
It's cold outside, is it necessary to wear a coat?
B
有必要，不然会感冒。
Yǒu bìyào, bùrán huì gǎnmào.
It is necessary, otherwise you'll catch a cold.
做作业
A
这个题目很难，我需要帮忙吗？
Zhège tímù hěn nán, wǒ xūyào bāngmáng ma?
This question is hard, do I need help?
B
先自己试试，有必要再问老师。
Xiān zìjǐ shì shì, yǒu bìyào zài wèn lǎoshī.
Try it yourself first, ask the teacher if necessary.
Related words and contrasts
related
重要
zhòngyào
important
'必要' means necessary; '重要' means important. They are related but not the same.
opposite
多余
duōyú
unnecessary, superfluous
Means something is extra or not needed.