1. vi.发生　 occur by chance
2. vi.碰巧，恰巧　 chance; have the good or bad fortune
3. vi.偶然发现　 find by chance

　～ again　再次发生
　～ commonly　通常发生
　～ easily　容易发生
　～ frequently　经常发生
　～ historically　在历史上发生
　～ lately　最近发生
　～ logically　合乎逻辑地发生
　～ mysteriously　神秘地偶然发生
　～ opportunely　恰好出现
　～ promptly　很快地发生
　～ spontaneously　自发
　～ subsequently　随后发生
　～ usually　通常发生
　～ along　偶然出现，碰巧来到
　～ in with　偶然和…碰见
　～ on　偶然发现、找到或遇到…
　～ on the book　偶然发现这本书
　～ to　降临于，注定为，发生于，对…造成损害或损失
　～ upon sb in the street　在街上偶然碰见某人

　It happened under my eyes.　我亲眼看见这事发生的。
　How did this happen?　这事是怎么发生的?
　The accident happened at three o'clock.　事故是3点钟发生的。
　A crowd soon collected at the crossroad to see what had happened.　十字路口上很快就聚集了一群人，都想看看出了什么事。
　Who can foretell what will happen to the world in 1000 year's time?　谁能预言1000年后这个世界将会发生什么事?
　A near-total news blockout kept the outside world guessing as to what was really happening at the summit.　由于对会议实行了全面新闻封锁，外界人士对首脑会议只能进行猜测。
　It's impossible to anticipate when it will happen.　要预料何时会发生是不可能的。
　She exclaimed that she would not allow that to happen.　她大声说她不允许那件事发生。
　Try to describe exactly what happened before the accident.　设法描绘一下就在事故发生前的确切情景。
　If you happened to be in town, would you ask about it?　你要是有机会进城，可不可以问问这件事?
　You happened to be out when I came to your house.　我到你家时，你正好出去了。
　He happened to be going that way too.　他恰好也正往那边走。
　She happened to have just finished reading the book.　碰巧她刚读完那本书。
　Do you happen to know her telephone number?　你知道她的电话号码吗?
　If you happen to see Miss Yang, please tell her to come to my office after supper.　要是你碰见杨小姐，请告诉她晚饭后到我办公室来。
　There happened to be a severe drought that year.　那年适逢严重旱灾。
　It happens that his elder sister is a close friend of mine.　恰好他姐姐是我的一个好朋友。
　It happened that the harvest was bad that year.　恰好那年收成不好。
　It so happened that I had no money with me.　碰巧我身上没带钱。
　It so happened that he had to be present at a meeting.　他碰巧得去参加一个会议。

 ♣ as it happens〔happened〕
　碰巧　by chance
　We met her only yesterday, as it happens.　我们只是在昨天才与她碰巧相遇。
　They were all out, as it happened.　真巧，他们全出去了。
 ♣ happen along　(v.+adv.)
　出现　arrive by chance
　She happened along just as we were about to leave.　当我们将要离开的时候，她突然来访。
　Guess who happened along while I was waiting for the bus.　你猜猜看，我在等公共汽车时谁碰巧也来了?
　You were obviously annoyed that the child had happened along.　那孩子此时出现你显然很生气。
 ♣ happen on〔upon〕　(v.+prep.)
　巧遇，偶然发现　find or meet by chance
　〔说明〕 happen on〔upon〕通常不用于进行体，也不用于被动结构。
　I happened on John in the park.　我在公园里碰巧遇到约翰。
　We happened on an old country inn, and stopped to have a meal.　我们碰巧发现一家古老的乡村小旅店，就停下来吃了一顿饭。
　The children happened on a charming little stream near the camp.　孩子们无意间在宿营地附近发现了一条可爱的小溪。
　He happened upon the perfect solution to the problem just as he was about to give up his research.　正当他要放弃自己的研究时，他偶然发现了解决这个问题的最佳方案。
 ♣ happen to　(v.+prep.)
　发生在…身上　(of an event) take place and have an effect on
　〔说明〕 happen to通常不用于进行体。
　The boy is crying. What has happened to him?　那孩子在哭，他怎么啦?
　If anything should happen to you, follow my advice.　万一你碰上什么意外，照我的话去做。
　The brakes failed. Has that ever happened to you?　车闸失灵了，你以前发生过这种情况吗?
　What happened to him next?　后来他怎样了?
　Be careful; don't let anything happen to that child.　小心些，别让那个孩子出任何事。
　A bad accident happened to that family.　那家人遇到了极其不幸的灾祸。
　What has happened to your hand?　你的手怎么了?
　If anything happens to the machine, please let me know.　要是机器出了毛病，请告诉我。
 ♣ whatever happens〔happen what may〕
　无论发生什么　not care anything occur
　Whatever happens, you must survive all along.　不管发生什么事，你必须好好活着。
　We'll go to London tomorrow, happen what may.　不管发生什么情况，我们明天都要去伦敦。

 ♣ happen to sb, happen with sb
　这两者都是“某人发生了某事”的意思，前者可指坏事，也可指好事；而后者多指坏事。试比较：

 ♣ happen, occur, take place
　这三者均可作“发生”解。它们的区别是：
1. happen和occur往往表示事情的发生带有偶然性， happen是一般用语， occur是较正式用语；take place常指按计划“发生”。例如：
　The explosion happened〔occurred〕 during an exercise near the town.　在离市镇不远的地方演习时发生了爆炸。
　The talk is scheduled to take place tomorrow morning at eight o'clock.　预定明早8时举行会谈。
2. 当表示具体事情的名词作主语时，用happen和occur都可，如果不是表示具体事情的词则多用happen. 在否定句里一般用occur. 例如：
　These events happened〔occured〕 last year.　这些事是去年发生的。
　What happened after I left?　我走后发生了什么事情?
　It didn't occur to him to ask for help.　他没想到请别人帮忙。
 ♣ 下面两个句子意思不同：

　第1句中的it是形式主语，第2句中的it是第三人称代词，相当于the thing.

　［同义词］ appear, arise, chance, come about, develop, event, experience, follow, occur, result, take place, turn out
　［词源］　中古英语happenen（机缘，偶然发生）