―do/does/did+v‖表示“一定，务必”，“确定，肯定”。
(1)Dobecarefulwhencrossingthestreet.
(2)Theydidcometoseeyouyesterday,butfailedtomeetyou.
(3)Hedoeslookwell.他的确看起来气色很好。
二、It强调句型
1.基本结构:Itis/was+被强调部分+that+其他部分,
强调人时可换用who/whom
①强调主语：TomandMarkoftencometoseeme.
②强调宾语：Youmetmeyesterday.
Weputoffthesportsmeetbecauseoftherain.（原因）[强调句操练]ImetTominthestreetyesterday.
2.◆检验是否为强调句的方法:将itis/was…that...省略后句子仍是完整的,即为强调句，否则就不是。
a.Itwasin1937thatIfirstmetchairmanMao.(强调句)
b.Itwas1937whenIfirstmetchairmanMao.(定语从句，1937先行词)
3.对not...until...结构的强调
(1)Ididn’tgotobeduntilmyfathercamebacklastnight.
→ItwasnotuntilmyfathercamebackthatIwenttobedyesterday.
4.强调句的一般疑问和特殊疑问句
(1)一般疑问句:Is/Was+it+被强调部分+that+其他部分？
Itwasin1939thattheSecondWarbrokeout.（一般疑问句）
→___________________________________
(2)特殊疑问句:特殊疑问词+is/was+it+that+其他部分
Whowasitthatbrokethewindow
※强调句特殊疑问句用于宾词性从句中要用陈述句语序
Idon’tknowwhoitwasthatbrokethewindow.(陈述句语序)
5.情态动词在强调句中的运用：
Itmightbe...that...,和Itmusthavebeen...that...的句型
（1）Itmightbehisfatherthatyouarelookingfor.
（2）Itmusthavebeenhisbrotherthatyoumet.
（3）一般疑问:情态动词+itbe+被强调部分+that+其他
Mightitbeintheofficethatsheleftherkeys
（4）特殊疑问:特殊疑问词+情态动词+itbe+that+其他部分
Wheremightitbethattheaccidenthappened
6.强调句中的主谓一致问题
被强调部分如果是原句的主语，who或that后面谓语的人称和数应和原句的主语一致。
①ItisMaryandTomwhooften_____(do/does)gooddeeds.
②Itwasthedriverratherthanthetwooldmentoblamefortheaccident.
A.is
B.thatis
C.are
D.whoare
应该为这起事故负责的是司机而不是这两位老人。
7.与强调句易混的几个句型
Itis/hasbeenfivemonthssinceIarrivedinNewYork.
我到纽约已经五个月了。
Itwaslongbeforehegaveananswer.过了好久他才答复我。
Itwasnotlongbeforeheworkedoutthedifficultmathsproblem.
不一会儿他就把那道数学题解出来了。
Itwillbeyearsbeforehecomesback.过几年他才回来。
Itwasfiveo’clockwhenhecametoseeme.
④Itis+adj.+that从句
Itisclearthatnotallboyslikefootball.
【典型例题】
1.（05天津）Itiswhatyoudoratherthanwhatyousay____matters.
A.that
B.what
C.which
D.this
2.（05安徽）Thatwasreallyasplendidevening.It’syears____Ienjoyedmyselfsomuch.
A.when
B.that
C.before
D.since
3.（08重庆）Itwasnotuntilmidnighttheyreachedthecampsite.
B.when
C.while
D.as
4.(06辽宁）Itwasafterhegotwhathehaddesired____herealizeditwasnotsoimportant.
C.since
5.08全国II）ItwasinNewZealand___ElizabethfirstmetMr.Smith.
B.how
D.when
6.（06山东）Ijustwonder____thatmakeshimsoexcited.
A.whyitdoes
B.whathedoes
C.howitis
D.whatitis
8.（06全国卷二）Itwasnotuntilshegothome____Jenniferrealizedshehadlostherkeys.
C.where
D.before
9.（07山东）---Wheredidyougettoknowher
---Itwasonthefarm____weworked.
A．thatB．thereC．whichD．where
10.Itwastwentymilesfromourcitytothevillage____theaccidenthappened.
C.then
D.where
11.（04北京）TheForeignMinistersaid,―____ourhopethatthetwosideswillwork