干貨知識：普通專升本英語語法之動詞不定式

    動詞不定式
    1．常用形式：一般主動式to do, 一般被動式to be done
    完成主動式to have done, 完成被動式to have been done
    進(jìn)行式to be doing
    2．語法功能：可作主語、表語、賓語、賓補(bǔ)、定語和狀語（即除謂語之外的各種成分）。例如：
  （1）主語：To master a foreign language is very important.
  （2）表語：My job is to drive them to the company every day.
  （3）賓語：Do you want to visit the Great Wall?
    Can you give us some advice on what to do next?
  （4） 賓補(bǔ)：The teacher advised us to have a rest first.
    I didn’t notice them come in.

    注：see, hear, watch, notice, have, make, let等動詞后作賓補(bǔ)的動詞不定式不帶to, 但變?yōu)楸粍诱Z態(tài)以后（即不定式作主補(bǔ)時）要帶to, 其中l(wèi)et sb. do sth. 變?yōu)楸粍邮綖閟b. is let do sth.
    help（幫助）后作賓補(bǔ)的動詞不定式可帶to，也可不帶to. 即help sb.(to)do sth.
  （5） 定語：不定式位于所修飾的名詞，代詞之后，如：Who was the first one to set to the top of the hill yesterday? /He is the man to depend on/to believe in.
  （6）狀語： in order to
    A．目的狀語：She reads China Daily every day so as to improve her English.
    注：in order to 可以位于句首或句中，so as to 不能位于句首。
    B．原因狀語： I’m glad to see you . 注：這種“be＋形容詞＋不定式”結(jié)構(gòu)，其不定式有時也可視為賓語，如：He is eager to go to college./ She is sure to come here.
    C．結(jié)果狀語：They lived to see the liberation of their home town.他們一直活到見到家鄉(xiāng)解放。
    在“too…to…”結(jié)構(gòu)中表“太…結(jié)果不能”，如：He is too weak to do the work.
    注：too之前如果有only, only too 表“非常”、“很”意，此時不定式不再表否定意，而表肯定意。如：They are only too lucky to go abroad for a visit. 他們很幸運去國外訪問。
    另外，too后如果是happy, glad之類形容詞時，不定式也表肯定意。
    如：She was too happy to meet her old friend in the street.
    在“形容詞/副詞＋enough＋不定式”結(jié)構(gòu)中表“足以能…”，如：He is strong enough to do the work .
    3．復(fù)合結(jié)構(gòu)不定式（for sb. to do sth.），可作主語、表語、賓語、定語和狀語。for 本身無意義，sb.可稱之為不定式的邏輯主語。例如：I think it necessary for him to go there at once.（復(fù)合結(jié)構(gòu)不定式作賓語）。
    注：當(dāng)作表語用的形容詞表示不定式的邏輯主語的性質(zhì)或特征時，不用for, 而用of,
    如：It is kind of you to help me .（相當(dāng)于You are kind to help me .）這類形容詞有g(shù)ood,nice,kind,wise, clever, foolish, silly, stupid, careless, impolite（不禮貌）等。right, wrong既可用于for sb. to do sth. 也可用于of sb. to do sth. 例如：It’s right/wrongg for him to do the work alone.
    4．疑問詞＋不定式：可作主語、表語或賓語。如：How to finish the work in time is a problem.（主語）We don’t know when and where to go .（賓語）
    5．動詞不定式的否定式（not to do sth.），語法功能同不定式肯定式。