學(xué)習(xí)英語之不定式作主語內(nèi)容匯總分享

　　To +動(dòng)詞原形

　　Not to do

　　解釋：具有動(dòng)詞的性質(zhì)，作賓語，狀語/具有名詞的性質(zhì)，作主語/具有形容詞性質(zhì)，作定語/具有副詞的性質(zhì)，作狀語。除謂語不可作之外，其他都可。

　　一般式：to do

　　進(jìn)行時(shí)：to be doing

　　完成時(shí)：to have done

　　完成進(jìn)行時(shí)：to have been doing

　　to do:表示動(dòng)作發(fā)生在謂語之后，I want to go home.與謂語動(dòng)詞幾乎同時(shí)發(fā)生

　　to be doing :表示與謂語動(dòng)詞同時(shí)發(fā)生

　　to have done:發(fā)生在謂語動(dòng)詞之前 Someone was considered to have done something.

　　to have been doing :動(dòng)作從過去開始一直持續(xù)到謂語動(dòng)詞這個(gè)動(dòng)作的發(fā)生

　　(1)動(dòng)詞不定式作主語時(shí)，謂語動(dòng)詞常常用單數(shù)。例如：

　　To do morning exercises is useful for our health. 做早操有利于我們的健康。

　　To sweep the floor is my duty every day. 每天打掃地板是我的責(zé)任。

　　(2)如果動(dòng)詞不定式太長，常常用it作形式主語，而將真正的主語——動(dòng)詞不定式后置。例如：

　　It took me half an hour to walk there.我走到那兒花了半小時(shí)的時(shí)間。

　　It's important for us to learn English well.對我們來說，學(xué)好英語是重要的。

　　下面歸類五種句型：

　　①It+be+名詞+to do

　　It's our duty to take good care of the old.

　?、贗t takes sb+some time+to do

　　How long did it take you to finish the work?

　　③It+be+形容詞+for sb+to do

　　It is difficult for us to finish writing the composition in a quarter of an hour.

　?、躀t+be+形容詞+of sb+to do

　　It is stupid of you to write down everything (that) the teacher says.

　?、軮t seems(appears)+形容詞+to do

　　It seemed impossible to save money.

　　注意：

　　在句型③中，常用表示客觀情況的形容詞，如：difficult,easy,hard,important,impossible,necessary 等;在句型④中，常用careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise等 表示贊揚(yáng)或批評的詞。在不定式前的sb，可看作其邏輯主語。這一句式有時(shí)相當(dāng)于Sb is+形容詞+to do句式。

　　如：

　　It's kind of you to help me with my English.=You are kind to helpme with my English.

　　一定要先收藏起來再接著學(xué)哦~