53．go out①＝move out of；as of a room，a country，a bus，etc．意为“出去”。例如：She's gone out for a walk．她出门散步了。②＝leave the house to go somewhere，意为“离家”。例如：We never went out when we were young．我们小时候从未离开家。③＝become extinguished； as of lights or candles，意为“（火；灯）熄灭”。例如：The lights suddenly went out and we were in the dark．灯突然灭了，我们处在黑暗中。
54．grow up ＝develop from child to man or woman，意为“长大成人”。例如：I want to be a pilot when I grow up．我想长大以后当飞行员。When he GREw up，he became a great scientist．他长大后，成了一位伟大的科学家。
55．had better（do）＝to be wise or obliged to；should or must，意指“最好做……”。例如：You had better do what he told you．你最好按他说的做。
56．happenvi．①＝take place（偶然）发生（to）：The accident happened at the crossing．这个事故发生在十字路口。②＝do sth．by chance（＋不定式）碰巧：I happened to know his new telephone number．我碰巧知道他的新号码。My birthday happens to be New Year's Day．我的生日正好是新年这天。
happen是不及物动词，不能用于被动语态。其用法有：
①happen通常与to连用，表示“偶然发生”。例如：
What happened to him last night？他昨晚发生了什么事情？
When and where did the accident happen？事件是什么时候在哪儿发生的？
②happen后接不定式，意为“恰好；碰巧”。例如：
I happened to be out this morning．今天早晨我碰巧出去了。
