英语:第六页第七题阿~~~
be to have/has done
什么意思?
还有daily language point的第一题
为什么用as?
be to do是将要做
be to have done是将做未做,算是虚拟语气吧
as单独引导定语从句时,先行词可以是一个词,但更为常见的是:它的先行词是整个主句,有时也可以是一个短语。例如:
The two brothers were satisfied with this decision,as was agreed to beforehand两兄弟对此决定都很满意,这项决定事前已得到他们的同意。(先行词是decision)
She is late,as is often the case.她迟到了,这是经常的事。(先行词是整个主句)
He married her,as was natural.他和她结婚了,这是很自然的。(先行词是整个主句)
To shut your eyes to facts,as many of you do,is foolish.视而不见———你们好多人都是如此———是愚蠢的。(先行词是整个不定式短语)
B.as与which的区别
以上前三个例句中的as都可用which来代替,但它们之间在用法和语义上是有区别的。
1.语义上的区别:
as作为关系代词仍多少保留“理由,“比较,“方式,“等同等意义,而which没有这些意义。因此,由as引导的定语从句通常在意义上不可与主句相悖,而且一般是肯定的,对主句意义起相辅作用,表示“正如等意义;而which从句则不受此限(参见《新编英语语法》章振邦主编P.1331)。例如:
Mother treats me just like ababy,which I can't bear.妈妈对我就像小孩,我真受不了。
She has married again,which was unexpected.她又结婚了,这是大家没有预料到的。
上面两句中的which都不宜用as。
但当否定的定语从句作正面理解,对主句起相辅作用而不是与其相悖时,仍可用as。例如:
He turned his eyes on Philip's face,as he had not done for ten years.(=...,as he had done ten years before.)他转过身来看着菲利普的脸,他十年来没有这样看过他的脸了。(=他转过身来像十年前那样看着菲利普的脸。)
He really can't lend you the money,as you might not
realize.(=...,as you must
realize.)他的确不能把那些钱借给你,这一点你可能意识不到。(=你必须意识到。)
2.用法上的区别:
a)在结构为“主语+谓语+宾语的定语从句中作主语时,通常用which,而不用as。例如:
He saw the girl,which delighted him.他看见了那个女孩,这使他很高兴。
He admires Mrs.Brown,which surprises me.他钦佩布朗太太,这使我很惊奇。
b)as引导的定语从句的位置较灵活,可后置、可前置、也可置于句中;而which引导的定语从句只能置于先行词之后。例如:
He is an Englishman,as /which you know from his accent.他是英国人,这你从他的口音就能知道。
Taiwan,as you know,is an inseparable part of China.你知道,台湾是中国不可分割的一部分。
As is announced in the papers,our country has launched another
man-made earth satellite.报纸宣布,我国又发射了一颗人造地球卫星。