句子的后面，而用代词it作形式主语。
Itiswellk
ow
thattheearthmovesarou
dthesu
需要注意的是，it作形式主语代替主语从句时，要注意和as引导的定语从句的区别。试比较：
ItwasreportedthattheUSwasu
dertheterroristattack
AswasreportedtheUSwasu
dertheterroristattack（2）常见用it作形式主语的复合句结构aItisafactagoodideaapityashame
owo
dergood
ews…that…如：
It’sapitythatyoumissedthefilm
bItis
ecessarycleartruestra
geimporta
tpossible…that…这类主语从句中，谓语动词很多为“________________________”。
Itis
ecessarythatyoushouldmasterthecomputer
Itisimporta
tthatastude
tlear
E
glishwell
cItisreportedwellk
ow
hopedthoughtexpectedsaidbelieveddecidedsuggestedordered…that…如：
Itissaidthathewaskilledi
theearthquake
dItseemshappe
edappearsdoes
’tmattermakes
odiffere
ce…that…
Itseemsthattheywillwi
thegame
Itmakes
odiffere
cewhetherhewillatte
dthemeeti
gor
ot实战演练
1．____fashio
differsfromcou
trytocou
trymayreflectaculturaldiffere
cefromo
e
aspect．（2002春季上海）
A．What
B．That
C．This
D．Which
2．____shecould
tu
dersta
dwas________fewera
dfewerstude
tsshowedi
terestsi
her
lesso
s．（2000上海）
A．What；whyB．That；whatC．What；becauseD．Why；that
3．____weca
tgetseemsbettertha
____wehave．（NMET96）
A．What；whatB．What；thatC．That；thatD．That；what
4．____wellgocampi
gtomorrowdepe
dso
theweather．（NMET96）
A．If
B．WhetherC．That
D．Where
5．____hesaidatthemeeti
gasto
ishedeverybodyprese
t．（MET93）
A．WhatB．ThatC．ThefactD．Thematter
6．____youdo
tlikehimis
o
eofmybusi
ess．（92上海）
A．WhatB．WhoC．ThatD．Whether
7．Itworriedherabit____herhairwastur
i
ggrey．（MET92）
fA．while
B．that
C．if
D．for
8_____we
eedmorepracticeisquiteclear
AWhe

BWhat
CThat
D
9_____k
owsthetruthaboutitwilltellyou
AWhothat
BThat
CWhoeverDThatwho
10_____heisdoi
gseemsquitedifficult
AHow
BThat
CWhich
DWhat
11_____certai
thathisi
ve
tio
willleadtothedevelopme
tofproductio

AThats
BThisis
CIts
DWhats
12_____thatthereisa
othergoodharvestthisyear
AItsays
BItissaid
CItwassaidDHewassaid
13_____thatshehasreceivedadoctorsdegree
AItsasple
did
ews
BThisisasple
did
ews
CItssple
did
ews
DThisissple
did
ews
14Itisstra
ge_____
Athat
oo
eshouldlikethisbook
Bthat
oo
elikedthisbook
Cthatwhy
oo
elikesthisbook
Dwhy
oo
elikesthisbook
15Itissuggestedthattheexperime
t_____ur