Unit 2 Discover useful structures-高中英语人教版（2019）选择性必修第三册

2030·HELLOTHERE小清新（汇报：第一PPT）WehavemanyPowerPointtemplatesthathasbeenspecificallydesignedtohelpanyonethatissteppingintotheworldofPowerPointfortheveryfirsttime.UNIT2HEALTHYLIFESTYLEDiscoveringusefulstructures目录contents1.直接放在句首作主语2.It做形式主语3.和疑问词构成短语作主语4.只能接不定式口诀1.Toseeisto

believe.2.To

do

this

isto

cut

the

foot

to

fit

the

shoe.3.To

say

isonethingandto

do

isanother.

总结1：

从位置上看，动词不定式作主语，通常放在句首。当句子主语和表语都是非谓语时，通常要__保持一致_，例如：Toseeistobelieve.=Seeingisbelieving.1.Tobeworkingalldaylongisabore.

2.Tohavemadethesamemistaketwiceisunforgivable.3.Toloveandtobelovedisthegreathappiness.总结2：动词不定式作主语可以有不同的时态和语态形式。有tobedoing；behavedone;tobedone.主动语态被动语态一般时todotobedone进行时tobedoing完成时tohavedonetohavebeendone语态时态Itisn’trightforustostophalfway.

=Tostophalfwayisnotright.2.It’skindofyoutothinksomuchofus.

=Youarekindtothinksomuchofus.总结3：

动词不定式的逻辑主语常用_____________来表示，当形容词修饰动词不定式时，此时常用介词_____。当表语形容词表示不定式的逻辑主语的性质或特征时，则用介词____。for/of+sbforof1.It’sourduty

todothat.

2.It’samistakenottohelpthem.

3.Itmustbegreatfun

toflytothemooninaspaceship.总结4：以上三个句子的表语都是_______，它们可归纳为:一个共同句式：____________________________名词it+be+n+todosth1.Ittookmemorethananhourtodomyhomework

yesterdayevening.2.It

will

takeusalongtimetowalkthere.3.Howlongdoesittaketogetthere?

4.Howmuchdiditcostyoutosendthepackage?总结5：

以上四个句子是动词不定式作真正主语，由

it作形式主语引导的句子，它们的谓语是_____________。它们的共同句式是_________________________________________________，表示某人花多少时间或金钱做某事。

take/costittakes

(costs)sbsometime

/moneyto do sthHowtousethecomputerisaquestion.Wheretoputthebikes

isbeingdiscussed.Whenandwheretohavethemeetinghasnotbeendecided.总结6：_____________构成不定式短语作主语。疑问词包括疑问代词who、whom、what、which、whose以及疑问副词when、where和how。此外连接词whether也适用。此时，疑问词+todo结构可以转化为一个__________，例如：Howtousethecomputerisaquestion.

=主语从句Howwecanusethecomputerisaquestion.疑问词+todoHowlongdoesittakeforyou_______(get)therebybike?Howmuchdiditcostyou_______(send)thepackagetoBeijing?It’simportant_______youtowalkaftersupper.It’sveryrude______youtoturnyourbacktoyourteacherandrefusetoanswer.togettosendforof实战练习Tomakefriendswiththesenaughtyboys_______(be)nice.When______(hold)

themeetinghasnotbeendiscussedyet.Itseemedapity_____________(waste)somuchtimeonthetaskwithoutachievingourgoal.Tochangeor____________(change)isaquestionwehavetothinkabouteveryday.

is

to

holdtohavewastedtobechanged只能接不定式动词口诀：决定想做计划需要同意;能做被用来做的事;迫不及待下决心做过去常常未能做的事;记忆：decidetodosth.want/wouldliketodosth.planto