一、under 用于标示一个较为低的部位，意为“在（或到、根据）…下边”，比如：

　　Have you looked under the bed?

　　你看看了床下边沒有？

　　She placed the ladder under the window.

　　她把人字梯站在窗子下边。

　　The dog squeezed under the gate and ran into the road.

　　狗从门底下钻出来，跑到大道上来了。

　　He hid under the bed.

　　他躲在床下边。

　　They stood under a tree to avoid getting wet.

　　她们立在树底下以防打湿。

　　二、under 用于表明在某事表层下，一般是被某事遮盖或贴紧某事，意为“在…表层下”，比如：

　　She was holding a folder under her arm.

　　她腋窝下夹着一个文件夹名称。

　　Because I'm a bad swimmer, I often go under and swallow a lot of water.

　　由于我游水游得不太好，我经常下到水中吞并许多水。

　　In AD 79 the city of Pompei was buried under a layer of ash seven metres deep.

　　公年79年，庞贝城被埋在一层7米深的余烬下。

　　She put the thermometer under my tongue.

　　她把温度表放到我嘴巴下边。

　　She used to hide her diary under her pillow.

　　她过去常常把日记藏在枕芯下边。

　　They found the body buried under a pile of leaves.

　　她们发觉遗体被埋在一堆落叶下边。

　　My sister was hidden under several layers of blankets.

　　我表妹藏在多层毛毯下边。

　　The main fields are under wheat.

　　关键的农田被玉米遮盖。

　　三、under 用于表明假如一本书，一篇文章或一条信息内容在某一独特的题目或归属于某一分类下，那麼他们就可以在该题目下被寻找，或者按这一题目在明细或者公共图书馆中被寻找，比如：

　　If it's not under ‘sports’, try looking under ‘games’.

　　假如在“体育竞赛”项下查不出，就试一下“手机游戏”项吧。

　　Books on Ansel Adams will probably be under Art or Photography.

　　有关安塞尔·拉塞尔的书很有可能会被归于造型艺术或摄影类。

　　四、under 用于表明总数低于某一数据，等同于 less than，意为”低于，低于，不够“；或表明年纪低于某一年纪，等同于 younger than，意为”比…年青“，比如：

　　All items cost/are under a pound.

　　全部物件的价钱都是在一英镑下列。

　　The discount applies only to children under ten.

　　折扣优惠只适用十岁下列的少年儿童。

　　If you get under 50 percent, you fail the exam.

　　假如你不上50%，你考試就不过关。

　　五、under 用于表明在什么的危害下产生的事儿或結果，意为”由…导致，受…危害“，比如：

　　The wall collapsed under the strain.

　　墙面因承担不上压力而塌陷了。

　　Now that the deadline is approaching we all feel under pressure.

　　如今最终限期快到了，大家都觉得有工作压力。

　　The chair broke under his weight.

　　桌椅在他的压力下坏掉。

　　The work was completed under very difficult conditions.

　　此项工作中是在十分艰难的标准下进行的。

　　六、under 用于表明根据，意为”依据，依照“，比如：

　　Under the current rules, you need the agreement of at least 6 out of 10 committee members.

　　依据现阶段的标准，你需要获得最少6/10联合会组员的愿意。

　　Under the terms of the lease you had no right to sublet the property.

　　按租期条文的要求，你没有权利转租房这房地产。

　　Is the television still under guarantee?

　　这台电视仍在质保期内吗？

　　七、under 用于表明处在某一全过程，意为”在…全过程中“，比如：

　　The town is under fire from the air.

　　这座城区遭受上空的战火围攻。

　　The patient is being kept under heavy sedation.

　　这一患者已经服很多镇静药。

　　She'll have to go under anaesthetic for the operation.

　　她得接纳麻醉剂才可以动手术。

　　The proposals are now under consideration by the Board of Governors.

　　股东会已经决议这种建议。

　　The situation is still not under control.

　　形势仍未获得操纵。

　　八、under 用于表明在什么命令或命令下，意为”在…命令或指令下“，比如：

　　They're under strict orders not to discuss the situation.

　　她们收到严苛的指令，不能探讨这一状况。

　　He's under doctor's orders to cut down on fatty food and to drink no alcohol for at least six months.

　　医师指令他降低高脂肪食物，最少六个月内不喝酒。

　　九、under 用于表明在别人或某一机构下，意为”由…操纵（或管理 *** ，运营，执政）”，比如：

　　He's a Colonel, with hundreds of soldiers under him.

　　他是元帅，手底下有百余名兵士。

　　The country is now under martial law.

　　这一我国现阶段在 *** 中。

　　The coinage was reformed under Elizabeth I .

　　美国币制在伊利莎白一世时期作了改革创新。

　　She has a staff of 19 working under her.

　　她手底下有19个员工工作中。

　　I wonder what Britain was like under the Romans.

　　想要知道希腊人执政下的美国是哪些的。

　　十、under 用于表明应用一个独特的专有名词，一般并不是真正的专有名词，意为“用，以（某一姓名）”，比如：

　　He writes under the name John le Carré.

　　他以罗伯特·勒梅帝的为名创作。

　　For his own safety, he has to operate under a false name/an alias.

　　为了更好地自身的安全性，他迫不得已用平假名/笔名动手术。

　　十一、under 用以复合词中，表明做得不足或小于某一规范，比如：

　　undercooked potatoes

　　未煮开的马铃薯

　　underprivileged children

　　贫困儿童

　　We're all overworked and underpaid.

　　大家都工作过度，薪水低。

　　His boss says he's under-performing at work.

　　他的老总说他工作业绩较差。