prepositionuk/ˈʌn.dər/ us/ˈʌn.dɚ/

under preposition LOWER POSITION

A1 in or to a position below or lower than something else, often so that one thing covers the other在（或到）下面；在（或到）下方

He hid under the bed.他躲在床底下。

In AD 79 the city of Pompei was buried under a layer of ash seven metres deep.公元79年，庞贝古城被湮没在7米深的火山灰下。

She put the thermometer under my tongue.她把温度计放到我的舌头下面。

She was holding a folder under her arm (= between her upper arm and the side of her body).她腋下夹着一个文件夹。

They stood under a tree (= below its branches) to avoid getting wet.他们站在树下避雨。

specialized geography If a piece of land is under a particular type of plant, that plant is growing on the whole of that area.（土地）被…植物覆盖的

The main fields are under wheat.主要的农田都种了麦子。

If a book, article, or piece of information is under a particular title, you can find it below or following that title in a list, book, library, etc.（书、文章或信息）属于…类别，在…项下

Books on Ansel Adams will probably be under Art or Photography.关于安塞尔·亚当斯的书很可能属于艺术或摄影类。

Custard? That comes under Desserts.蛋奶甜羹？应该在甜点类中找。

More examples

The children squealed in delight when they saw all the presents under the Christmas tree.

I bent down to look under the bed.

A dog lay under the table, gnawing on a bone.

She used to hide her diary under her pillow.

There was no soap, so I just quickly rinsed my hands under the tap.

under preposition LESS THAN

A2 less than少于；低于

All items cost/are under a pound.所有物品价格均低于1英镑。

The discount applies only to children under (the age of) ten (= younger than ten).折扣仅面向10岁以下儿童。

If you get under 50 percent, you fail the exam.如果考分低于总分的一半，你就没有及格。

Opposite

over

More examples

You can get travel concessions if you are under 26.

It's against the law to leave children under a certain age alone in the house.

I managed to get all three suitcases for under $200.

She ran her first marathon in just under three hours.

You can walk from here to the station in under ten minutes.

under preposition EXPERIENCING

B2 happening during, as a result of, or according to a particular situation, event, rule, etc.在…情况下；由于；根据

The work was completed under very difficult conditions.这项工作是在极端困难的情况下完成的。

Now that the deadline is approaching we all feel under pressure.由于最后期限就要到了，我们都感受到了压力。

The chair broke under his weight (= because he was too heavy for it).他太重了，椅子承受不住被压坏了。

Under the current rules, you need the agreement of at least 6 out of 10 committee members.根据现有的规则，你必须取得委员会十位成员中至少六人的同意。

under attack, consideration, discussion, etc.

B2 in the process of being attacked, considered, discussed, etc.遭受攻击／正在考虑／正在讨论（等等）

The town is under fire (= is being attacked) from the air.该城正遭受空袭。

The proposals are now under consideration by the Board of Governors.理事会正在考虑这些提议。

The situation is still not under control.局势仍然没有得到控制。

under sedation, anaesthetic, etc. UK

treated in the way mentioned处于镇静剂／麻醉剂的作用之下

The patient is being kept under heavy sedation.病人正处于服药后的深度镇静状态。

She'll have to go under anaesthetic for the operation.手术前必须给她施行麻醉。

old-fashioned She's been under the doctor for a viral infection.她因病毒感染接受了医生治疗。

be under an impression/belief

B2 to believe something, often wrongly（常指错误地）以为／相信

He was under the mistaken belief that I was in charge.他误以为是我在负责。

More examples

An adult under British law is someone over 18 years old.

He was under attack for daring to criticize the prime minister.

The procedure is carried out under local anaesthetic.

I imagine he's under a lot of pressure at the moment.

Except under clearly defined circumstances, it is illegal in Britain for a company to purchase its own shares.

under preposition CONTROL

controlled or governed by a particular person, organization, or force受…的控制（或管理）

He's a Colonel, with hundreds of soldiers under him (= obeying his orders).他是一名上校，手下有数百名士兵。

I wonder what Britain was like under the Romans (= during the time when the Romans controlled Britain).我想知道英国在罗马人统治时期是什么样子。

People born under (= during the period of) the zodiac sign Pisces are supposed to be dreamy and artistic.有人认为，双鱼座的人爱幻想、有艺术细胞。

be under orders

to have been ordered to do something奉命，受命

They're under strict orders not to discuss the situation.他们被严令不得讨论时局。

He's under doctor's orders (= has been told by a doctor) to cut down on fatty food and to drink no alcohol for at least six months.医生告诫他要在至少半年的时间内少吃油腻食物、滴酒不沾。

More examples

The group flourished under her firm leadership.

He served under Harold Wilson as Transport Minister.

Sleeping Beauty lay under the wicked fairy's spell until the prince woke her with a kiss.

As a young painter, he studied under Picasso.

Eastern Slavonia is to revert to Croatian government rule next year after a transitional period under U.N. administration.

under preposition NAME

using a particular name, especially one that is not your real name用，以（尤指假名）

He writes under the name (of) John le Carré.他用约翰•勒•卡雷这个名字创作。

For his own safety, he has to operate under a false name/an alias.为了自身安全，他不得不使用假名／化名。

Idiom(s)

be/fall under sb's influence/spell

adverbuk/ˈʌn.dər/ us/ˈʌn.dɚ/

below the surface of something在下面

Because I'm a bad swimmer, I often go under and swallow a lot of water.因为游泳水平很差，我经常沉到水下，呛很多水。

More examples

The waves came crashing over my head and I could feel myself being sucked under by the currents.

I like swimming but I don't like putting my head under.

A big piece of rope netting was laid on the ground and we had to crawl under as quickly as we could.

"Oh no, it's starting to rain." "I've got my umbrella - quick, get under."

She was stuck on the other side of a locked door, but I got the key and slid it under to her.

Idiom(s)

go under

prefixuk/ʌn.dər-/ us/ʌn.dɚ-/

not enough or not done as well or as much as is necessary不足，不够

undercooked potatoes没煮熟的土豆

underprivileged children贫困儿童

We're all overworked and underpaid.我们全都超时工作，但薪水却很低。

His boss says he's under-performing (= not doing as well as he should) at work.老板说他在工作中表现欠佳。

Compare

over- (MORE THAN)

below下面

underwear内衣

an underpass地下通道