高一英語Friendship教學(xué)案
他學(xué)習(xí)非常用功，正如我們大家都知道的。
as is known to all, he is the best student in our class.（as代表整個句子，作主語）
眾所周知，他是我們班最好的學(xué)生。
常用的這種類似插入語的句式有as is said above, as is already mentioned above, as is known to all, as it is, as is often the case, as is reported in the newspaper等。
（6）as, which 非限定性定語從句
由as, which 引導(dǎo)的非限定性定語從句，as和which可代整個主句，相當(dāng)于and this或and that。as一般放在句首，which在句中。
例如：as we know, smoking is harmful to one's health.
正如我們所知，吸煙有害健康。
the sun heats the earth, which is very important to us.
太陽加熱地球，這對我們非常重要。
典型例題：
a) alice received an invitation from her boss, ______ came as a surprise.
a. it b. that c. which d. he
解析：答案c。此為非限定性從句，不能用 that修飾，而用which，it和he 都使后
句成為句子，兩個獨立的句子不能單以逗號連接。況且選he句意不通。
b) the weather turned out to be very good, ______ was more than we could expect.
a. what b. which c. that d. it
解析：答案b。which可代替句子，用于非限定性定語從句，而what不可。that 不能用于非限定性定語從句，it不為連詞，使由逗號連接的兩個句子并在一起在英語語法上行不通。
c) it rained hard yesterday, ______ prevented me from going to the park.
a. that b. which c. as d. it
解析：答案b。as 和which在引導(dǎo)非限制性定語從句時，這兩個關(guān)系代詞都指主句所表達的整個意思，且在定語從句中都可以作主語和賓語。但不同之處主要有兩點：
ⅰ. as引導(dǎo)的定語從句可置于句首，而which不可。
ⅱ. as代表前面的整個主句并在從句中作主語時，從句中的謂語必須是系動詞；
若為行為動詞，則從句中的關(guān)系代詞只能用which.。
在本題中，prevent由于是行為動詞，所以正確選項應(yīng)為b。
（7）必須用that而不用which引導(dǎo)定語從句的情況：
①先行詞是不定代詞all, few, little, much, something, nothing, anything等。
例如：all that we have to do is to practice every day.
我們必須做的全部是每天練習(xí)。
②先行詞被序數(shù)詞或形容詞最高級所修飾。
例如：the first lesson that i learned will never be forgotten.
我學(xué)的第一門課永遠難忘。
this is the best film i’ve ever seen.
這是我曾經(jīng)看過的最好的電影。
③先行詞被all, any, every, each, few, little, no, some等修飾。
例如：i have read all the books (that) you gave me.
我讀完了你給我的所有書籍。
④先行詞被the only, the very, the same, the last修飾時，
例如：he is the only person that/(who) i want to talk to.
他是我唯一想交談的人。
⑤先行詞既有人又有物時，
例如：they talked of things and persons that they remembered.