1NEEDsomething that is necessary is what you need to have or need to do 必要的,必需的,必不可少的 → essential
The booklet provides all the necessary information about the college.
这本小册子提供了关于那所学院的所有必需信息。
No further changes were considered necessary.
没有必要作出进一步的改变。
absolutely/really necessary
The police are advising motorists to travel only if their journey is absolutely necessary.
警方建议驾驶员如非万不得已不要驾车出行。
it is necessary (for somebody) to do something
It’s not necessary to wear a tie.
不一定要打领带。
The doctor says it may be necessary for me to have an operation.
医生说我可能需要做手术。
make it necessary (for somebody) to do something
Falling profits made it necessary to restructure the business.
利润下滑使得公司必须重组。
necessary for (doing) something
A good diet is necessary for maintaining a healthy body.
想保持身体健康,合理饮食必不可少。
if/when/where necessary
I’ll stay up all night, if necessary, to get it finished.
如有必要,我会熬个通宵把这事做完。
Register
In everyday English, instead of saying it is necessary for somebody to do something, people usually say that someone has to do something: 在日常英语中,人们一般不说it is necessary for sb to do sth,而是说someone has to do sth
The doctor says it might be necessary for me to have an operation. → The doctor says I might have to have an operation. 医生说我可能必须得做手术。
2necessary connection/consequence etcMUSTa connection, result etc that must exist and cannot be avoided 必然的联系/结果等
The closure of the factory was a necessary consequence of increased competition from abroad.
工厂倒闭是来自国外的竞争加剧的必然结果。
Examples from the Corpus
necessary connection/consequence etc• Normativepositivismasserts what legal positivists deny, namely that there is a necessary connection between law and positivemorality.• Men. come and go in their lives, but there is no necessary connection between motherhood and marriage.• It is further easy to see that there is no necessary connection between subsidy-free prices and Ramsey-optional prices.• The difficulty is finding any necessary connection between two cases.• That stratification would occur as a necessary consequence of the alienation of labour.• These are, however, necessary consequences of the division of labour and the consequentrole of trust in social relationships.• In neither ease was the omission a necessary consequence of the intellectualstance of the two schools.• Neither is upwardmobility, rising income or independence a necessary consequence of their diligence.
3a necessary evilMUSTsomething bad or unpleasant that you have to accept in order to achieve what you want 〔为实现目的不得不接受的〕不得已的事,难免的坏事
Mr Hurst regarded work as a necessary evil.
赫斯特先生把工作看成是迫不得已的事情。
Examples from the Corpus
a necessary evil• I, for one, consider yard work to be a necessary evil.• Mr Waldegrave's shambolicperformance in the pressconference was a necessary evil.• We do not look at government as a necessary evil.• It may be a necessary evil, but it is surely an evil.• However, the authors, like most others then and now, saw those shortcomings as a necessary evil in maintaining control.• They're a necessary evil, like the woman who sawed off all my lovelyhair.• Lawyers are a necessary evil that I try to use as little as possible due to their cost.• Bureaucracy was also a necessary evil to cope with the ravages of war.• They viewed such methods as a necessary evil, unavoidable yet somehow beneath their dignity.
THESAURUS
necessary used to describe something that you need to have or do 必需的,必要的
Make sure you bring the necessary documents with you.
一定要带好所需的文件。
It may be necessary for you to have a small operation.
你可能需要做个小手术。
essential very important and necessary, especially in order to be healthy, successful etc 〔尤为健康或取得成功〕非常必要的,必不可少的
Vitamins are essential for healthy growth.
维生素对于健康成长必不可少。
The tourist industry is an essential part of the Spanish economy.
旅游业是西班牙的经济支柱。
vital extremely important and necessary, especially in order to avoidserious problems 〔尤为避免重大问题〕必不可少的,非常重要的
A vital piece of equipment on the spacecraft had stopped operating.
航天器上的一个重要设备停止了运转。
It is vital that the aid is sent immediately.
必须马上派出救援。
compulsory if something is compulsory, you must do it because of a rule or law 〔根据法律或法规规定〕必须做的,强制性的
Maths and Science are compulsory subjects.
数学和科学是必修课。
All new staff undergo a compulsory training course.
所有新员工都必须参加一个培训课程。
obligatory if something is obligatory, you must do it because of a rule or law. Obligatory is more formal than compulsory 〔根据法律或法规规定〕必须做到的,义务的〔obligatory 比compulsory正式〕
The use of seatbelts is obligatory.
系安全带是强制性的。
Safety regulations have made it obligatory for all competitors to wear fist protectors.
安全条例规定所有参赛者都必须戴拳套。
mandatory if something is mandatory, you must do it because it is the law. Mandatory is more formal than compulsory and sounds stronger 依法必须做的,强制性的〔mandatory比compulsory正式,语气也更加强烈〕
School attendance is mandatory.
上课出勤是必须的。
a prisoner serving a mandatory life sentence
依法被终身监禁的犯人
requisite /ˈrekwəzət/ formal [usually before noun] the requisite things are the ones that you need to have in order to do something 〔为了做某事〕需要的,必要的,必备的
The other candidates lacked the requisite skills.
其他求职者缺少必要的技能。
nthe requisite evidence needed for a successful prosecution
Examples from the Corpus
necessary• She explainedwhy change was necessary.• Add a second layer if necessary.• Jennie told Katharine to be aware of this and to correct any fault as necessary.• Computers are as necessary as textbooks in schools.• They also make any necessarycriticisms and suggestions more easily acceptable when they are offered.• He produced the necessarydocuments and handed them to her.• Fats in our diet are necessary for both heat and energy.• The doctor says it may be necessary for me to have an operation.• This was clearly necessary for their analysis since it allowed them to aggregate data over different drivers.• Much doubling, therefore, is necessary in the tutti.• It will be necessary to close the pool while the repairs take place.• On his eighteenth birthday, his parents had believed it necessary to commit the act that would decisively save their only child.• But take another step back and it is no longer necessary to preserve the species.• If necessary, we will have to employ some outside people to finish the job.
VERBS | ADVERB | PREPOSITION | PHRASESVERBS➤appear, be, prove, seem顯得必要;必要;證明必要;看似必要▸➤become變得必要▸➤remain仍然必要▸➤make sth使⋯成為必要◇The cold weather has made it necessary to protect the crops.天氣寒冷,莊稼必須加以保護。➤believe sth, consider sth, deem sth, feel sth, find sth, regard sth as, see sth as, think sth相信⋯必要;認為⋯必要;視⋯為必要;感覺⋯必要;發現⋯很必要◇Make any alterations you consider necessary.你認為有必要的都可以修改。◇You may find it necessary to readjust the wheels from time to time.你可能會發現不時調整輪子很有必要。ADVERB➤really, strictly確實/完全必要◇I was determined not to stay in the hospital for any longer than was strictly necessary.我決定,除非極為必要,否則決不在醫院多待一天。➤absolutely絕對必要➤hardly幾乎無需▸➤logically邏輯上必要▸➤medically醫學上必要PREPOSITION➤for對⋯必要◇qualifications which are necessary for work with the under-fives照顧 5 歲以下兒童必需的資格PHRASES➤if necessary如果必要的話◇These measures will be enforced, if necessary, by the army.如果必要,軍隊會強制執行這些措施。➤as necessary, when necessary, where necessary需要時;必要處◇We are here to give help and support when necessary.如有需要,我們隨時提供幫助和支援。◇Editorial changes have been made where necessary.在必要之處作了編輯上的改動。
necessary adj. ⇨necessary (necessary to do sth)⇨inevitable (a necessary condition/consequence)necessary
adjective
➡ See also the entry for essential另见essential条necessary ♦︎ compulsory ♦︎ mandatory ♦︎ requisite ♦︎ obligatory ♦︎ forced ♦︎ involuntaryThese words all describe sth that sb has to do or have.这些词均表示必须做的、必要的、强制性的。PATTERNS AND COLLOCATIONS 句型和搭配◆it's necessary / compulsory / mandatory / obligatory for sb to do sth◆it's necessary / compulsory / mandatory / obligatory to do sth◆forced / involuntary repatriation◆almost / legally compulsory / obligatory■necessarythat is needed for a purpose or a reason必需的;必要的◆It may be necessary to buy a new one.也许有必要买个新的了。◆Only use your car when absolutely necessary.不得已时才开车。◆If necessary, you can contact me at home.必要的话,我在家时你也可以和我联系。◆I'll make the necessary arrangements.我会做一些必要的安排。OPPunnecessary ⇨ unnecessary see also necessary ⇨ inevitable, necessitate ⇨ meanverb3■compulsory kəmˈpʌlsəri (ratherformal) that must be done because of a law or rule(按法律或规定)必须做的,强制的◆It is compulsory for all motorcyclists to wear helmets.所有骑摩托车的人都必须强制戴头盔。◆English is a compulsory subject at this level.英语在这一级别是必修科目。OPPvoluntary,optional ⇨ voluntary1 see also compulsion ⇨ pressure2■mandatory ˈmændətəri; NAmEˈmændətɔːri, BrE also mænˈdeɪtəri (formal) that must be done because of a law(按法律)必须做的,强制的◆It is mandatory for blood banks to test all donated blood for the virus.血库一律要按规定检查所有捐献的血液是否含有这种病毒。◆The offence carries a mandatory life sentence.这种罪行依照法律要判无期徒刑。■requisite ˈrekwɪzɪt [only before noun] (formal) necessary for a particular purpose必需的;必备的;必不可少的◆She lacks the requisite experience for the job.她缺少做这份工作所必需的经验。■obligatoryəˈblɪgətri; NAmEəˈblɪgətɔːri (formal) that must be done because of a law or rule(按法律或规定)必须做的,强制的◆It is obligatory for all employees to wear protective clothing.所有员工必须强制穿防护服。ⓘ Obligatory is sometimes used humorously before a noun to talk about sth that often exists or is done, but that is not really necessary at all. * obligatory有时用于名词前,描述常有的或常做的但根本无甚必要的事,为幽默用法◆The hotel has a terrace with comfy chairs for that obligatory cocktail.这家旅馆有个露台,摆放着舒适的椅子,供人们喝上一杯那似乎是不可或缺的鸡尾酒。OPPoptional ⇨ voluntary1NOTE辨析 Compulsory, mandatory or obligatory?Compulsory is used especially in the contexts of education, business and employment. * compulsory尤用于教育、商务和职业语境◆compulsory education / schooling / reading / subjects义务教育;必读材料;必修科目◆compulsory insurance / liquidation / purchase / redundancy / retirement强制性保险;强制清算/购买/裁员/退休Mandatory is used especially in the context of the law. * mandatory尤用于法律语境◆a mandatory sentence / penalty / duty / requirement法定判决;依法惩处;法定义务/条件Obligatory is often used to talk about rules and laws relating to safety, for example in sport or the workplace. * obligatory常用于描述跟安全相关的规定和法律,如体育运动的规则或工作场所的规章◆Recently safety regulations have made it obligatory for all competitors to wear fist protectors.最近,所有参赛者都必须按安全规定戴拳套。■forced [usually before noun] happening or done without you wanting it to被迫的;不得已的;非自愿的◆Many are unhappy about the forced repatriation of the refugees.很多人对强制遣返难民感到不满。◆I hope there will be no need for the forced sale of any property.我希望不会有强行变卖财产的必要。■involuntaryɪnˈvɒləntri; NAmEɪnˈvɑːlənteri [usually before noun] (ratherformal, written) happening or done without you wanting it to被迫的;不得已的;非自愿的◆The distinction between voluntary and involuntary unemployment is often blurred.自愿失业和非自愿失业之间的区分往往很模糊。OPPvoluntary ⇨ voluntary1NOTE辨析 Forced or involuntary?Forced often suggests that sb is forcing sb to do sth; involuntary suggests that it is circumstances, not another person, that forces sb to do or be sth. * forced常指受他人所迫,involuntary指受环境所迫或所限◆forced unemploymentHowever, involuntary can also be used when it is in fact the actions or decision of another person that forces sb to do sth, as a more formal and less direct (or less honest) way of saying forced.不过,involuntary可用于指事实上是另一个人的行为或决定迫使某人做某事,是forced较为正式和不太直接(或不太坦率)的说法◆the forced / involuntary repatriation of the refugees对难民的强制性遣返