thereis和itis用法的区别
thereis和itis用法的区别
thereis和itis用法的区别
thereis和itis用法的区别
thereis表示“有”的意思,例如:
Thereisappleonthedesk.这儿有一个苹果在桌上.
I.Itis+adj.+todosomething结构
句中it是形式主语,真正主语是动词不定式todosomething.因此也可以表达为todosomething+is+adj..
e.g.Itisamazingtodrivepastfieldswhichseemtogoonforeverorwholehillscoveredwithneatrowsofgrapevines.
本句形式主语为it.真正主语todrive…grapevines移到了句子后部,使句子变得平稳,不致主语太长.如果把真正主语放在前面,那么整个句子就显得头重脚轻.因此,就用it作为先行主语.
这种结构还有两种动词不定复合结构.
1.Itis+adj.+forsomebodytodosomething
e.g.Itwasverydifficultforthemtoflybecausemenhavenotgotwings.
此句真正的主语是动词不定复合结构forthemtofly.其中them是tofly的逻辑主语.
2.Itis+adj.+ofsomebodytodosomething
e.g.Itissensible_____youtobringanumbrellainsuchweather.
A.inB.for
C.withD.of
答案为D.这里sensible跟逻辑主语you的关系是表达人的特点、性格、本质等.像此类形容词还有kind,foolish,clever,wise,friendly等.
II.Itis+名词+todosomething结构
e.g.Itisgreatfuntoseethepandaswalkinginthezoo.
III.另外,it作先行主语时还有其他用法
1.it+及物动词+宾语+不定式
e.g.Itcostme100dollarstorepairthecar.
Ittakesmetwohourstofinishmyhomeworkeveryday.
Itgavemegreatpleasuretowatchthem.
2.it+be+名词/形容词+doing
e.g.Itisnousestudyingforanexamatthelastminute.
Itisawasteoftimetalkingtohim.
Itispleasantsittinghere