as的用法

字號(hào):

as可以作連詞、介詞及關(guān)系代詞?,F(xiàn)將其用法小結(jié)如下:
    一、 as作連詞的用法:
    1. 作"當(dāng)……的時(shí)候",引導(dǎo)時(shí)間狀語(yǔ)從句。注意與when、 while的用法區(qū)別。
    ① when作"當(dāng)……的時(shí)候"解,可以指較短的(一點(diǎn))時(shí)間,也可指一段時(shí)間。如:
    When he was at college, he could speak several foreign languages.
    When the clock struck twelve, all the lights in the street went out.
    ② while常表示一段較長(zhǎng)的時(shí)間或一個(gè)過(guò)程,強(qiáng)調(diào)主句謂語(yǔ)動(dòng)詞與從句謂語(yǔ)動(dòng)詞同時(shí)發(fā)生。如:
    Work while you work. Play while you play.
    ③ 但屬下列情形時(shí),只用as, 而不用when或while。
    A) 用于表示同一個(gè)人的兩種動(dòng)作交替進(jìn)行,指"一邊……,一邊……"。如:
    The girl dances as she sings on the stage.
    He looked behind from time to time as he went forward.
    B)表示兩個(gè)同步發(fā)展的動(dòng)作或行為,譯為"隨著……"。如:
    As time went on / by, she became more and more worried.
    As children get older, they become more and more interested in the things around them.
    C)表示兩個(gè)短促行為或事件幾乎同時(shí)發(fā)生。如:
    I thought of it just as you opened your mouth.
    Just as the flying worm hit her face, she gave a loud cry.
    D) 后接名詞表示某一年齡段時(shí),用as。如:
    As a young man, he was active in sports.
    2. as=since, 作"既然"、"由于"解,引導(dǎo)原因狀語(yǔ)從句,常用來(lái)表示已為人們所知或顯而易見(jiàn)的原因或理由。如:
    As / Since you''''re not feeling well, you may stay at home.
    As he wasn''''t ready in time, we went without him.
    3. as=in the way that, 作"像"、"按照……的方式"解,引導(dǎo)方式狀語(yǔ)從句。如:
    He speaks English as Americans do.
    Remember, you must do everything as I do.
    4. 用于as...as...或not so/ as...as...中,前一個(gè)as是副詞,后一個(gè)as是連詞,引導(dǎo)比較狀語(yǔ)從句。如:
    They helped the old man as often as possible.
    I don''''t speak English so/ as well as he does.
    5. 作"雖然"、"盡管"解,引導(dǎo)讓步狀語(yǔ)從句。常用倒裝語(yǔ)序,即adj. /adv. / n.+as +主語(yǔ)+謂語(yǔ)+主句。如:
    Tired as they were, they walked on.
    Child as he is, he knows a lot. (child前不用冠詞)
    二、 as作關(guān)系代詞,引導(dǎo)定語(yǔ)從句,作"正如"、"這一點(diǎn)"解。如:
    He is very careful, as his work shows.
    As is well-known, Taiwan belongs to China.
    as的這種用法,請(qǐng)看2001年的高考題:
    is known to everybody, the moon travels round the earth once every month.
    A. It B. As C. That D. What
    (字母下劃?rùn)M線的為正確答案)
    另外,當(dāng)先行詞被the same, such等詞修飾時(shí),常用as來(lái)引導(dǎo)定語(yǔ)從句。如:
    Such a clever boy as he can learn anything quickly.
    I was reading the same book as he bought yesterday.
    三、 as作介詞的用法:
    as引導(dǎo)的介詞短語(yǔ)大多用作狀語(yǔ),as譯為"作為";少數(shù)情況可引起賓語(yǔ)補(bǔ)足語(yǔ)。如:
    As a League member, I''''ll take the lead in everything. (狀語(yǔ))
    She works as a doctor. (狀語(yǔ))
    They have me as one of their own children.(引起賓語(yǔ)補(bǔ)足語(yǔ))