如题所述
it 是形式主语，代替getting the children off to bed.
这不是to do 句型！！
这不是to do 句型！！
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第1个回答 2011-07-20
It is句型的种类
参见课件it 的用法
（1） It is time (for sb.) to do sth. //It is (high) time that sb. did sth.(虚拟语气) 该是做某事的时候了。 例如：
It is high time that we tried our best.// It is time for us to try our best.
（2）It is + 形容词（+of / for sb.）+ to do sth.
（3）It is + 形容词 + that + sb. + (should) do sth.（虚拟语气）
能用于这个句型的形容词有strange、wonderful、natural、good、proper、right、wrong、well、fortunate、important、necessary、useless、likely、probable、impossible等。有时可省去should而直接用动词原形。如：
It is important that we should pay close attention to grain.
It is natural that he（should）say so.
（4）It is no use/ good + doing sth. 做某事无意义
It is no use trying again = It is of no use to try again.
（5）It is + 被强调部分 + that/who + …
Was it in the street that you met her?
Who was it that called him" comrade”?
It was not until yesterday that I met my old friend.
It is in a small factory that my brother is going to work. 注意上述各句为强调句型的“考点”）
比较：It is a small factory where my brother is going to work.（定语从句）
（6）It is said/reported/announced/ (well) known … that… 据说/据报道…
（7）It is/was + 时间 + since … 从……已多久了。
It is/ has been three years since I met him in Beijing.
It was a long time since I (had) lived in that small mountain village with these farmers.
（8）It is + 时间 + before …
这个句型和上面句型中时间都是时间段，如long、years、months、weeks、five days、three hours、twenty minutes等。不过主句的时态多用一般将来时或一般过去时。
It will be several years before we meet again.
我们要过好几年才能再见面。
It was not long before they set out for the front.
不久他们就出发去了前线。
（9）It is /was/will be the first/second/ … time that …第几次做某事
It is the first time that I have been here.
It was the second time that he had seen the film.
（10）It is up to sb. to do sth … 应由某人做某事。
It is up to you to decide whether we start or not.
您本题为句型4.
参见课件it 的用法
（1） It is time (for sb.) to do sth. //It is (high) time that sb. did sth.(虚拟语气) 该是做某事的时候了。 例如：
It is high time that we tried our best.// It is time for us to try our best.
（2）It is + 形容词（+of / for sb.）+ to do sth.
（3）It is + 形容词 + that + sb. + (should) do sth.（虚拟语气）
能用于这个句型的形容词有strange、wonderful、natural、good、proper、right、wrong、well、fortunate、important、necessary、useless、likely、probable、impossible等。有时可省去should而直接用动词原形。如：
It is important that we should pay close attention to grain.
It is natural that he（should）say so.
（4）It is no use/ good + doing sth. 做某事无意义
It is no use trying again = It is of no use to try again.
（5）It is + 被强调部分 + that/who + …
Was it in the street that you met her?
Who was it that called him" comrade”?
It was not until yesterday that I met my old friend.
It is in a small factory that my brother is going to work. 注意上述各句为强调句型的“考点”）
比较：It is a small factory where my brother is going to work.（定语从句）
（6）It is said/reported/announced/ (well) known … that… 据说/据报道…
（7）It is/was + 时间 + since … 从……已多久了。
It is/ has been three years since I met him in Beijing.
It was a long time since I (had) lived in that small mountain village with these farmers.
（8）It is + 时间 + before …
这个句型和上面句型中时间都是时间段，如long、years、months、weeks、five days、three hours、twenty minutes等。不过主句的时态多用一般将来时或一般过去时。
It will be several years before we meet again.
我们要过好几年才能再见面。
It was not long before they set out for the front.
不久他们就出发去了前线。
（9）It is /was/will be the first/second/ … time that …第几次做某事
It is the first time that I have been here.
It was the second time that he had seen the film.
（10）It is up to sb. to do sth … 应由某人做某事。
It is up to you to decide whether we start or not.
您本题为句型4.
