成人英語三級(jí)考試輔導(dǎo)：as,which非限定性定語從句詳解
As we know, smoking is harmful to one's health.
The sun heats the earth, which is very important to us.
典型例題
1)Alice received an invitation from her boss, ___came as a surprise.
A. it B. that C. which D. he
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(gè)獨(dú)立的句子不能單以逗號(hào)連接。況且選he句意不通。
2)The weather turned out to be very good, ___ was more than we could expect.
A. what B. which C. that D. it
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(hào)連接的兩個(gè)句子并在一起在英語語法上行不通。
3)It rained hard yesterday, ____ prevented me from going to the park..
A. that B. which C. as D. it
答案B.
as 和which在引導(dǎo)非限制性定語從句時(shí)，這兩個(gè)關(guān)系代詞都指主句所表達(dá)的整個(gè)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(diǎn)：
(1) as 引導(dǎo)的定語從句可置于句首，而which不可。
(2) as 代表前面的整個(gè)主句并在從句中作主語時(shí)，從句中的謂語必須是系動(dòng)詞;若為行為動(dòng)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(dòng)詞，所以正確選項(xiàng)應(yīng)為B。
As 的用法
例1. the same… as;such…as 中的as 是一種固定結(jié)構(gòu), 和……一樣……。
I have got into the same trouble as he (has).
例2. as可引導(dǎo)非限制性從句，常帶有'正如'。
As we know, smoking is harmful to one's health.
As is know, smoking is harmful to one's health.
As是關(guān)系代詞。例1中的as作know的賓語;例2中，它充當(dāng)從句的主語，謂語動(dòng)詞know要用被動(dòng)式。
As we know, smoking is harmful to one's health.
The sun heats the earth, which is very important to us.
典型例題
1)Alice received an invitation from her boss, ___came as a surprise.
A. it B. that C. which D. he
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(gè)獨(dú)立的句子不能單以逗號(hào)連接。況且選he句意不通。
2)The weather turned out to be very good, ___ was more than we could expect.
A. what B. which C. that D. it
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(hào)連接的兩個(gè)句子并在一起在英語語法上行不通。
3)It rained hard yesterday, ____ prevented me from going to the park..
A. that B. which C. as D. it
答案B.
as 和which在引導(dǎo)非限制性定語從句時(shí)，這兩個(gè)關(guān)系代詞都指主句所表達(dá)的整個(gè)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(diǎn)：
(1) as 引導(dǎo)的定語從句可置于句首，而which不可。
(2) as 代表前面的整個(gè)主句并在從句中作主語時(shí)，從句中的謂語必須是系動(dòng)詞;若為行為動(dòng)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(dòng)詞，所以正確選項(xiàng)應(yīng)為B。
As 的用法
例1. the same… as;such…as 中的as 是一種固定結(jié)構(gòu), 和……一樣……。
I have got into the same trouble as he (has).
例2. as可引導(dǎo)非限制性從句，常帶有'正如'。
As we know, smoking is harmful to one's health.
As is know, smoking is harmful to one's health.
As是關(guān)系代詞。例1中的as作know的賓語;例2中，它充當(dāng)從句的主語，謂語動(dòng)詞know要用被動(dòng)式。