巧辨before和until
在日常英语教学中,我们遇到学生问这样的一些问题:1.Hewillspendsixhoursathisdesk____hefinisheshiscomposition.A.beforeB.untilC.afterD.when
2.Thebikehitthetree____Icouldgetoff.A.whenB.beforeC.whileD.until
3.Iknockedatthedoorformorethanfiveminutes____Mrswhiteansweredit.A.untilB.whenC.afterD.before
4.Itwas____yesterday____be____thesecret.A.notuntil;that;knewB.until;when;knewC.notbefore;that;foundD.before;that;didn'tfind
怎样才能清楚地解释其选择的原因,这就涉及到until与before的区别问题。实际上,只要我们把握住两者使用时本身的含义及主句动词是终止性的,还是延续性的,肯定式,还是否定式两大点,就能容易地解决这类问题。
现详细阐明如下:一、在下列情况下,两者可互换用,但含义略有不同。before表示“在……之前”的意思,强调时间先后关系;而until表示“直到……才”的意思,主句是肯定句则表示主句动作的终止时间;主句是否定句则强调主句动作的起始时间。
1.主句为否定式终止性谓语动词。常见的动词open,start,leave,arrive,finish,stop等。
(1)Thenoiseofthestreetdidn'tstopuntil/beforeitwasmidnight.
(2)Thechildrenwon'tcomebackuntil/beforeitisdark.
(3)Ididn'tleavethelovelyboyuntil/beforehismothercamehome.
2.主句为肯定式、延续性谓语词,这类动词用stand,stay,talk,be,wait等。
(1)Helivedwithhisparentsuntil/beforehegraduatedfromschool.
(2)Iwillwaituntil/beforehecomestomyhelp.
(3)Ishallstayheeruntil/beforeyoucomeback.
二、在下列情况下,用before不用until。1.主句这肯定式、终止性谓语动词,只用before。
(1)HefellasleepbeforeIcouldtakeoffhisclothes.
(2)Wearrivedtherebeforeitatartedtorain.
(3)TheholidaycametotheendbeforIknewit.
(4)Healmostknockedmedownbeforehesawme.
2.主句谓语动词强调动词的迟缓性,只用before,常伴有时间段状语或时间段暗示。
(1)Itwasquitesometimebeforehefoundtheelephantatall.
(2)Wehadwalkedalongwaybeforewefoundsomewater.
(3)Wehadsailedfortwodaysbeforewesawtheland.
(4)Thefirelastedaboutfourhoursbeforethefirefighterscouldcountrolit.
(5)Itwasmidnightbeforemybrothercamehome.
3.如果强调从句谓语动作未发生,就发生主句谓语动作,只用before。常译为“未及”,“不”或“不等……就”。
(1)Wecanleaveearlyinthemorningbeforeitgetstoohot.
(2)ImustwriteitdownbeforeIforgetit.
(3)Wedowanttobuysomethingnowbeforepricesgoup.
4.表“与其说……倒不如”,“与其……毋宁……”只用before。
(1)IwouldgiveupmyjobbeforeI'dagreetobedismissed.
(2)Hewilldieofhungerbeforehewillsteal.
5.在某些特定句型中用before。
(1)Itwasnotlongbeforethewholecountryroseup.
(2)Itwillprobablynotbelongbeforetheyunderstandeachother.
三、下列情况一般区别用until1.主句是持续性谓语动词时,肯定、否定都可以,但意义完全不同。肯定表动作终止,而否定表动作开始。
(1)Wediscussedtheproblemuntil/beforehecameback.我们一直讨论到他回来。
(2)Wedidn'tdiscusstheproblemuntilhecameback.我们一直等到他回来后才讨论问题。
2.not…until句型尽管在某些情况下可与before互换用,但在强调句中一般仍用until。
(1)ItwasnotuntilhetoldmethatIknewit.
(2)Itwasnotuntilhefinishedhishomeworkthathewenthome.
综上所述,前面的4条选择题中,第1、3题强调动作发生的迟缓性应选before。第2题表动作未及发生就发生主句动作也应选before。第4题为强调句应选A项。