- physically in contact with and supported by (a surface)在…上：
on the table was a water jug
桌上是一个水罐
she was lying on the floor
她躺在地板上
a sign on the front gate.
前门上的一个记号。
- located somewhere in the general surface area of (a place)位于（某地）：
an internment camp on the island
岛上的一个拘留营
the house on the corner.
拐角上的房子。
- as a result of accidental physical contact with在…上：
one of the children had cut a foot on some glass
其中的一个孩子在玻璃上划伤了一只脚
he banged his head on a beam.
他把头撞在了一根横梁上。
- supported by (a part of the body)靠在（身体的某部位）上：
he was lying on his back.
他仰面躺着。
- on to到…上：
put it on the table.
把它放到桌上。
- in the possession of (the person referred to)带在身上; 拥有：
she only had a few pounds on her.
她身上只有几个英镑。
- forming a distinctive or marked part of (the surface of something)…上（形成该表面独特或有记号的一部分）：
a scratch on her arm
她手臂上的一道抓痕
a smile on her face.
她脸上的笑容。
- having (the thing mentioned) as a topic关于; 涉及：
a book on careers
一本关于事业的书
essays on a wide range of issues.
涉及广泛问题的短文。
- having (the thing mentioned) as a basis以…为基础：
modelled on the Act of 1954
效仿1954年法案的
dependent on availability.
依赖于能否得到。
- as a member of (a committee, jury, or other body)作为（委员会、陪审团等）成员：
they would be allowed to serve on committees.
他们将被允许成为委员会成员。
- having (the place or thing mentioned) as a target以…为目标; 向…：
five air raids on Schweinfurt
对施韦因福特的5次空袭
thousands marching on Washington.
向华盛顿进发的成千上万的人。
- having (the thing mentioned) as a target for visual focus（目光集中）在…上：
her eyes were fixed on his dark profile.
她的目光集中在他阴暗的侧面上。
- (often followed by a noun without a determiner) having (the thing mentioned) as a medium for transmitting or storing information以…为（传输或储存）介质：
put your ideas down on paper
把你的想法写在纸上
stored on the client's own computer.
储存在客户自己的电脑里。
- being broadcast by (a radio or television channel)由（电台或电视频道）播放：
a new 12-part TV series on Channel 4.
4频道播放的一部新的12集电视连续剧。
- in the course of (a journey)在（旅行）途中：
he was on his way to see his mother.
他在去看望母亲的路上。
- while travelling in (a public service vehicle)在（公共交通工具）上：
John got some sleep on the plane.
约翰在飞机上睡了一会儿。
- on to (a public vehicle) with the intention of travelling in it上（公共交通工具）：
we got on the train.
我们上了火车。
- indicating the day or part of a day during which an event takes place在（某天或某时段）：
reported on September 26
在9月26日发出的报道
on a very hot evening in July.
在7月的一个非常炎热的晚上。
- at the time of在…时：
she was booed on arriving home.
她回到家时遭到了嘲笑。
- engaged in忙碌于：
his attendant was out on errands.
他的助手出去办事了。
- regularly taking (a drug or medicine)靠, （经常）服用（药物）：
he is on morphine to relieve the pain.
他靠吗啡来缓解疼痛。
- paid for by由…支付：
the drinks are on me.
喝的饮料由我付账。
- added to增加：
a few pence on the electricity bill is nothing compared with your security.
跟你的安全相比, 电费单上多几分钱根本不算什么。
- physically in contact with and supported by a surface在上面：
make sure the lid is on.
确定盖子已盖上。
- (of clothing) being worn by a person（衣服）穿在身上：
sitting with her coat on
穿着大衣坐着
get your shoes on.
把鞋穿上。
- indicating continuation of a movement or action继续着：
she burbled on
她滔滔不绝地说下去
he drove on
他继续往前开车
and so on.
等等。
- further forward; in an advanced state向前; 前进中：
later on
后来
time's getting on.
时间渐晚。
- (of an entertainment or other event) taking place or being presented（娱乐演出等）上演; 进行中：
what's on at the May Festival
5月节的时候上演什么
there's a good film on this afternoon.
今天下午有一场精彩的电影上演。
- due to take place as planned（按计划）应发生：
the reorganization is still on.
重组仍在按计划进行。
- (of an electrical appliance or power supply) functioning（电器或电力供应）开着的：
they always left the lights on.
他们总是让灯开着。
- (of an actor) on stage（演员）在台上。
- (of an employee) on duty（员工）当班。
be on about
- Brit. informal talk about tediously and at length〈英, 非正式〉喋喋不休地谈, 滔滔不绝地谈：
she's always on about doing one's duty.
她总是滔滔不绝地谈要尽责。
be on at someone
- Brit. informal nag or grumble at someone〈英, 非正式〉对某人不断唠叨。
be on to someone
- informal be close to discovering the truth about an illegal or undesirable activity that someone is engaging in〈非正式〉几乎发现某人的非法行径。
be on to something
- informal have an idea or information that is likely to lead to an important discovery〈非正式〉（对重要发现）有头绪。
it's not on
- informal it's impractical or unacceptable〈非正式〉这是不实际的, 这是无法接受的。
on and off
- intermittently断断续续地：
it rained on and off most of the afternoon.
下午大部分时间都在断断续续地下雨。
on and on
- continually; at tedious length不断地; 持续地：
he went on and on about his grandad's trombone.
他一直不断地说着他爷爷的长号。
on it
- Austral. informal drinking heavily〈澳, 非正式〉大量喝酒, 酗酒。
on side
- supporting or part of the same team as someone else一边的（表示与某人支持同一球队或在同一个球队）。
on to
- moving to a location on (the surface of something)（移动到）…上：
they went up on to the ridge.
他们爬上了屋脊。
- moving aboard (a public service vehicle) with the intention of travelling in it登上（公共交通工具）：
we got on to the train.
我们上了火车。
what are you on?
- informal said to express incredulity at someone's behaviour, with the implication that they must be under the influence of drugs〈非正式〉（用于表示对某人行为的惊奇, 暗含他一定吸毒了）你吃错药啦？
you're on
- informal said by way of accepting a challenge or bet〈非正式〉（用于表示接受挑战或打败）一言为定。