join on . attach oneself to 附随；依附于

The people were hurrying to see the parade，and we joined on at the rear．人们赶去看游行，我们也跟在后面。

join on . attach；fix 装上；接上

They joined the wires on and made the necessary new connection．他们把电线接了起来，接通了所需的新线路。

join up . offer oneself as a recruit；join the army 参军；入伍

He joined up at the age of twenty．他二十岁参了军。

On leaving collage，my brother joined up．我的兄弟大学毕业后参军了。

join up . connect；link together 连接

The electrician joined the wires up．电工把电线接好了。

join up . form or enter into an alliance or league；link up 组成或参加联盟；会合

The two companies were ordered to join up with each other at Bridge number three before dawn．那两个连奉命于黎明前在三号桥会师。

judge by . judge from . form an idea or opinion by basing one's judgement on 由…判断

Judging by what you say，I assume you don't agree with me．根据你的话推测，我想你是不同意我了。

 jump at . take or accept quickly and gladly 欣然接受

Johnny jumped at the invitation to go swimming with his brother．乔尼欣然接受邀请，同个哥哥一块去游泳。

Alice would jump at the chance of going to Egypt．艾丽丝会非常高兴地接受这次去埃及的机会。

The children jumped at the chance of visiting the television studios．孩子们立即同意去电视制作中心看看。

jump down somebody 's throat . reply sharply and angrily to  尖锐或粗暴地回答

He jumped down my throat at the mere mention of the subject．一提到这事，他就粗暴地回答我。

Even if I'm wrong，you needn't jump down my throat like that．即使我错了，你也用不着这样粗暴地对待我。

 jump on . criticize sharply or suddenly 严厉批评；突然斥责

He jumped on her for that misbehavior．他对她的错误行为进行了严厉的批评。

He'll jump on anyone who contradicts him．谁不同意他，他就骂谁。

 jump out of one's skin . be badly frightened；be very much surprised 惊吓；大吃一惊；吓了一跳

The door slammed with such a bang that I nearly jumped out of my skin．门砰地一声关上了，吓了我一跳。

 jump over . pass over；disregard or omit something intervening 忽略；遗漏；略去

Let's jump over all those items．让我们把那些项目全部略去吧。

As time was limited，the professor had to jump over the details．因为时间有限，教授只好把一些细节省掉了。

Aware that the listeners were absentminded，the reader jumped over some paragraphs without anyone noticing．意识到听众心不在焉，宣读者略去了一些段落，谁也没有发觉。

just about . nearly；almost 几乎；差不多

Just about everyone in town came to hear the mayor speak．城里几乎所有人都来听市长讲话。

just now . just at this moment此刻

Mr．Johnson isn't here just now．Will you please phone back later? 约翰逊先生现在不在这儿。你过一会儿回电话好吗?

just now . a little while ago刚刚

He came in just now；he is probably upstairs．他刚才进来过，现在可能在楼上。

just so . exact；exactly right 正是如此

His trousers were neatly pressed and his new jacket was just so．他的裤子烫得很匀整，新外套也是如此。

justified in . proved to be just or right…（是）正当的；…（是）应该的

Do you think he was justified in doing that? 你以为他那样做是应该的吗?

justified in . free from the penalty of sin…（是）无罪的

You are justified in shooting a man in self-defence．你为自卫而枪击一个人是无罪的。

keel over . turn upside down；tip over；overturn（船）倾覆；翻转

The boat keeled over，and all the passengers fell into the water．那条船翻了，乘客们都掉入水中。

The ship keeled over when it hit the rocks，and sank to the bottom with all its passengers and sailors．船触礁后倾翻了，连同所有的乘客和船员一起沉入了海底。

keel over . fall over in a faint；faint 晕倒

It was so hot during the assembly that two girls who were standing on the stage keeled over．因天气太热，在集合的时候两个站在台上的女孩晕倒了。

He keeled over with laughter when I told him the joke．我把笑话讲给他听时，他笑得前仰后合。

When the principal told the girl her father died，she keeled right over．校长告诉这女孩她父亲去世时，她当场昏了过去。

Several cadets keeled over from the heat during the parade．几个军校学生在检阅时因天气太热而晕倒。

keen on . interested in；fond of；eager to   . eager for .对…有兴趣；喜欢；渴望

I'm not very keen on jazz．我对爵士音乐不太感兴趣。

She is particularly keen on playing the piano．她对弹钢琴特别着迷。

Tom is not very keen on Stella．汤姆不太喜欢斯特拉。

keep a civil tongue in one's head . be polite in speaking 出言客气有礼；讲话不粗鲁

The bus driver began yelling at the woman and she told him to keep a civil tongue in his head．汽车驾驶员对那位妇女大声嚷了起来，而她却要他说话礼貌点。

Don't be rude；keep a civil tongue in your head．别那么粗鲁，说话要客气点。