（完整word版）since,before,when,after等的区别
高考英语常考句式——it is +时间+ since (before, when)…
请注意以下三个句式的区别和意思上的差异（其中的 is 根据情况可以有其他时态形式）：
龟苓膏的功效与作用>护发素的正确用法It is + 时间段 + since…的意思是“自从……以来有一段时间了”。
It is + 时间点 + when…的意思是“当……的时候时间是……”。
It is + 时间段 + before…的意思是“在……之前有一段时间”。
请看以下用例：
It’s ten years since they got married. 他们结婚到现在已经十年了。
It was past one o’clock when he came in. 他回来时已经一点多了。
It won’t be long before they understand each other. 过不了多久他们就会互相了解的。
有时翻译可以比较灵活：
It’s a long time since I met you last. 好久不见了。(直译：自上次见到你以来有很长一段时间了。)
It’s about three years since I last played basketball. 我差不多有三年没有打篮球了。(直译：自从我上次打篮球以来已差不多有三年了。)
请看有关高考题(答案为DDBCDC)：
1.That was really a splendid evening. It’s years _________ I enjoyed mylf so much. (安徽卷)
A.when
B.that
C. before
D.since
2.It was some time _________we realized the truth. (山东卷)
A.when
B.until
C.s ince
D.before
3.—Did Jack come back early last night?
—Yes. It was not yet eight o’clock _________he arrived home. (福建卷)
A.before
B.when
C.that
D.until
4.Scientists say it may be five or six years _________it is possible to test this medicine on human patients. (福建卷)
A.since
B.after
C. before
D.when
5.It was evening we reached the little town of Winchester. (天津卷)
A.that
B.until
C.since
D.before
6.It _________ long before we _________ the result of the experiment. (上海春)
A.will not be; will know
B.is; will know
C.will not be; know余音绕梁是什么意思
D.is; know
【全真模拟训练】
1.It was about midnight _________ we found the lost child, crying under a tree.
A.that
B.until C .when D.where
2.It's some time _________ I have spoken to you about this matter.
A.that
B.unless
C.si nce
D.until
3.It was ten _________ he stood at aunt’s door and rang the bell.
A.when
B.until
C.sin ce
D.that
4.I think it won’t be long _________ they understand each other.
A.when
B.until
C.sin ce
D.before
5.How plead I am tonight! It’s years _________ we had so great a time together.
A.when黄河的历史故事
B.that
C.be fore
D.since
6.It was some time _________ we realized how important the matter is.
A.when
B.until
C.sin ce
D.before
7.—Did you come home very late last night?
—No. It was just half past ven _________ I appeared before my parents.
A.that
B.when
C.un til
D.since
8.How time files! It ems like years _________ I last saw you.
A.when
B.that
C.si nce
D.before
9.It’s more than half a century _________ the People’s Republic of China was liberated.
A.when
小班语言活动B.that
C.si nce
金鱼草花
女童身高D.after
答案：1—5 CCADD 6—9 DBCC
描写心理活动的成语when
〔引导时间状语从句〕具体地说，它有以下几种含义：
1．表明一个动作发生的时候，另一个动作正在进行之中。例如：
When the teacher came into the classroom ，we were reading English．当老师走进教室时，我们正在读英语。
2．表明当某一动作正在进行时，另一动作发生了。如：
When Kate was flying a kite，she found a wallet lying on the ground．凯特正在放风筝时，她发现地上有个钱包。
〔特别提示〕当when从句放在主句之后时，它更强调某一动作的突然性，此时的when相当于and then，and suddenly，just at that time。如；
1．We were watching TV when the telephone rang．（＝We were watching TV and suddenly the telephone rang．）我们正在看电视，（突然）电话铃响了。
试比较：When we were watching TV，the telephone rang．我们正在看电视时，电话铃响了。
2．The boys were playing football when it began to rain．男孩子们正在踢球时，（不料）
开始下雨了。3．I was taking a walk when I came across Lily．我正在散步时，（没想到）遇见了莉莉。
特别是主句中有just，或when从句中有suddenly时，这种突然性更为明显、强烈。
Until 直到….为止, not… until直到…才
肯定形式表示的意思是"做某事直至某时"，动词必须是延续性的。否定形式表达的意思是"直至某时才做某事"。动词为延续性或非延续性都可以。
肯定句：
I slept until midnight. 我一直睡到半夜时醒了。
Wait till I call you. 等着我叫你。
（在肯定句中可用before代替Let”s get in the wheat before the sun ts.）
否定句：
She didn”t arrive until 6 o”clock.
