Unit2HealthyLifestyle動(dòng)詞不定式作主語課件高中英語人教版選擇性

動(dòng)詞不定式作主語Lookatthefollowingsentencesandpayattentiontotheitalicisedinfinitives.Findmoreinfinitivesinthereadingpassage.Inpairs,discusstheirmeaningsandfunctions.1.

Tochangebadhabitsisnevereasy.2.Ittookthesurgeonthreehours

tofinishmymother’slungsurgery.3.TojointhePeople’sLiberationArmy,itisrequiredformentoshaveofftheirbeards.

4.Itwasnotpolitetodisturbyourneighbourswithloudmusiclastnight.Theinfinitiveineachsentencefunctionsasthesubjectofthesentence.自主探究閱讀下列句子，

注意黑體部分的用法。1.It

takes

three

generations

to

make

a

gentleman．2.What

a

relief

it

is

for

us

to

succeed

in

our

experiment

at

last！3.It

was

careless

of

you

to

leave

your

umbrella

on

the

train．4.To

do

this

is

to

cut

the

foot

to

fit

the

shoe．5.To

read

without

reflecting

is

like

eating

without

digesting．我的發(fā)現(xiàn)（1）

所有黑體部分都是____________作主語。動(dòng)詞不定式（2）句1、2、3中黑體部分為____________作句子的真正主語，句中的it為

______主語。動(dòng)詞不定式形式（3）句4、5中直接用動(dòng)詞不定式作句子的______。主語探究點(diǎn)

動(dòng)詞不定式作主語1.動(dòng)詞不定式作主語，謂語動(dòng)詞常用第三人稱單數(shù)形式。To

see

is

to

believe.眼見為實(shí)。To

climb

up

the

mountain

road

is

easy

while

to

go

down

the

hills

is

hard.上山容易下山難。It

is

not

easy

to

find

your

way

to

the

town.要找到去這個(gè)小鎮(zhèn)的路并不容易。2.動(dòng)詞不定式作主語時(shí)，其位置有以下兩種：（1）將動(dòng)詞不定式置于句首。To

get

there

by

bike

will

take

us

half

an

hour.我們騎自行車到那兒需要半個(gè)小時(shí)。②Ittakessb+sometime+todosthHow

long

did

it

take

you

to

finish

the

work？你花了多長(zhǎng)時(shí)間來完成這項(xiàng)工作？（2）用it作形式主語，把作真正主語的動(dòng)詞不定式后置，常用于以下句式中：①It+be+名詞+to

do

sthIt's

our

duty

to

take

good

care

of

the

old.照顧好老人是我們的責(zé)任。③It+be+形容詞+forsb+todosthItisdifficultforustofinishwritingthecompositioninaquarterofanhour.在15分鐘內(nèi)完成這篇作文對(duì)我們來說太難了。④It+be+形容詞+ofsb+todosthItisstupidofyoutowritedowneverythingtheteachersays.你將老師所說的話全部記下來是很愚蠢的。在此結(jié)構(gòu)中，形容詞往往表示事物的性質(zhì)，如：important,necessary在此結(jié)構(gòu)中，形容詞往往表示人物的性格和特征，如：kind,impoliteV-ing一般性的抽象的重復(fù)性Todo一次性的具體的將要發(fā)生注意：Clearingtheblackboardisaneasyjob.Tocleartheblackboardisyourjobtoday．融會(huì)應(yīng)用單句填空（1）It

took

years

of

work

__________

（reduce）

the

industrial

pollution

and

clean

the

water.to

reduce（2）________

（walk）

is

a

good

form

of

exercise

for

both

the

young

and

the

old.Walking（3）___

is

difficult

for

him

to

admit

his

mistakes.It（4）It

was

selfish___him

not

to

share

his

dictionary

with

others.of（5）_________（finish）

the

task

will

take

a

long

time.To

finishPractice①Itiswrongforyou___________(skip)breakfast.②Although______isahardtasktoprotect

our

environment,wecan'thelpbutgoahead.③Ittookthedoctorabouthalfanhour_________(examine)theeyesofthebaby.④Itwasfoolish_____himtoendanger

hislifeinthatway.⑤Itisdifficult_____himtoliveonsuchasmallsalary.toskipittoexamineoffor和疑問詞構(gòu)成短語作主語

1.Howtousethephoneisaquestion.2.Wheretoputthecars

isbeingdiscussed.3.Whenandwheretohaveabarbecuehasnotbeendecided.①可用于該結(jié)構(gòu)的疑問詞疑問代詞:who,whom,what,which疑問副詞:when,where,how②常接該結(jié)構(gòu)的動(dòng)詞know,see,decide,tell,ask,consider,explain,learn,wonder③該結(jié)構(gòu)的句法功能:主語、賓語和表語Thequestioniswhentostartdevelopingsuchavaccine.問題是何時(shí)開始研制這種疫苗。(作表語)“疑問詞+不定式”結(jié)構(gòu)相當(dāng)于一個(gè)由疑問詞引導(dǎo)的名詞性從句。Howtousethecomputerisaquestion.

=___________________________________Howwecanusethecomputerisaquestion.不定式短語作獨(dú)立成分一些不定式短語可用作獨(dú)