It作形式主语常见用法

1、It 作形式主语常见句型1.lt + be + 形容词+ that-从句可用于此句型的形容词有 :wonderful, true ，good，right，wrong，( un)important，useless， surprising，disturbing,frightening,alarming,clear，unusual，lucky，certain, n ecessary 等。如： It is quite certain that he will be at the meeting.他将出席会议是无疑的。 It is surpris ing that he came late to sch

2、ool this morni ng.他今天早上迟至 U真 令人惊讶。 It is important that we (should) study hard.我们努力学习是很重要的。注意 :该句型中的形容词是(un) important, necessary等时，从句应为(should )+ 动词原形。It is important that we (should) learn English well.It is necessary that he (should) rember these words.2.It + be + 名词 + that-从句适用该句型的名词(词组)有 :a pit

3、y， an honor， a good thing， a fact， a surprise， a question,a shame,a custom, a truth,our hope, no wonder, good/bad manners 等。如： It is a pity (that) you missed the sports meeti ng last week.你错过了上周的运 动会太可惜了。 It is a fact that En glish is being accepted as an intern atio nal la nguage事实上 英语已经被作为一种国际语言而接

4、受了。3. Itseemappearhappen 的适当形式 that 从句。 It appeared that he was calm, but inside his heart was beating wildly with fear.4. It + be +过去分词 +主语从句，这类过去分词有：announ ced, believed, expected, hoped,decided, reported, said, shown等, 如：It is reported that 16 people were killed in the earthquake.It is not decide

5、d who will give the operation to the patient.5. It is time ( about time ,high time ) that .该句型中 that 后的从句应该用虚拟语气，值得注意的是 常用过去时态表 示虚拟 有时也用 should +动词原形， should 不能省。常译为是(正 是)的时侯。It is time that children should go to bed.= It is time that children went to bed.6. It is the first ( second . ) time that .用

6、完成时态。至于用什么完成时态，由主句的谓语动词的时态决定。如果 是一般现在时，后面从句用现在完成时态；如果是一般过去时，后面从句则用 过去完成时态。该结构中 that 可以省去； it 有时用 this 替换常译为是第一(二)次。It is the first time I have been here.= This is the first time I have been here.7. It + be + adj./ n. (for sb. / of sb.) + to do sth该句型中的形容词通常是表示事 物的特点或特征的如 difficult， hard， easy， impossible， necessary， important 等，此时用 fo r ；或表示人的性格特征或特点的如 nice， good， bad， kind，silly，foolish，wise，clever，careless，rude，brave，cruel，careful，grateful等，这时要用of。如： It is foolish of you to giv