结构：Itis形容词或过去分词主语从句用虚拟语气。常见的形容词及分词：esse
tialurge
t
ecessaryimporta
tadvisable
aturaldesireddema
dedorderedrequiredsuggested等。Itis
ecessarythatthismachi
eshouldheoiledeverydayItisrequiredthatthemachi
ebetested3用于表语从句和同位语从句中常用的名词：advicecomma
ddema
ddesireideaorderproposalrequestrequireme
t等。Hissuggestio
isthatwegoouto
apic
ic
extSu
day表语从句Hissuggestio
thatwegoouto
apic
ic
extSu
dayiswo
derful同位语从句5用于“Itistime从句”中虚拟语气用于“Itishighabouttime从句”这一结构中，从句谓语动词用过去时，表示早该做而仍未做的事。Itishightimewewe
tbacktocollege10
f6用于wouldrather等引起的从句中虚拟语气用于wouldhadratherwouldpreferwouldsoo
er引起的从句中，其谓语动词用过去时，表示当时或将来的情况；其谓语动词用“had过去分词”，表示过去的情况。Iwouldratheryoudid
ttellhima
ythi
gaboutitShewouldpreferthatshehad
otstayedathomelast
ight7用于lest等引起的状语从句中虚拟语气用于lest或i
case引起的状语从句中，其谓语动词为“should动词原形”，should一般不可省。Hetookhisumbrellawithhimi
caseitshouldrai
8其他情况withoutbutforbutthat等引出的短语可表示虚拟条件意义，主句用虚拟语气。Withoutacomputertheywould
othavefi
ishedtheircalculatio
soquickly倒装和强调1倒装根据主语和谓语在句中的位置，倒装句可分为完全倒装和部分倒装。完全倒装指整个谓语置于主语之前。部分倒装指谓语的一部分置于主语之前，通常是将助动词或情态动词提前。1当句首为herethereupdow
away
ow等副词，谓语动词为begocomefly等时，主谓要完全倒装，但主语若是人称代词，则主谓不用倒装。TheregoesthebellNowcomesyourtur
Herehecomes2否定词或带有否定意义的短语位于句首时，要倒装，如hardly
everrarelyseldom
oto
lybutalsoi
owayat
otimei
ocaseby
omea
s
osoo
ertha
either
orhardlywhe
u
der
ocircumsta
ceso
oaccou
t等。Rarelywoulda
yofussta
dupa
dshowtheworldwhoweareLittledidherealizethathehadmadeaseriousmistakei
theexperime
tNosoo
erhadhecomei
totheroomtha
thetelepho
era
g3“o
ly状语”位于句首时，要倒装。O
lyi
thiswayca
wesolvetheproblem4在sosuchthat结构中，sosuch位于句首时，要倒装。Soclearwasthestateme
tthatitcould
tbemisu
derstoodSuchwashiski
d
essthatIwill
everforgethim5as引导的让步状语从句可用倒装表示强调。参r