It的用法

　　(一)作人稱代詞

　　1、it代替前面(或后面)的單數(shù)名詞或分句等所表示的事物。

　　e.g. You cannot eat your cake but have it.(it代替前面的cake)

　　Although we cannot see it, there is air all around us. (it代替后面的air)

　　They say he has left town, but I don’t believe it. (it代替前面They…town分句中的情況)

　　2、代替有生命但不能或不必分陰陽性的東西(包括嬰兒)。

　　e.g. Yesterday we saw a big tree. It was fully twenty metres high. (it代替前面的tree)

　　The baby cried because it was hungry. (it代替前面的baby)

　　3、在某些習(xí)慣說法中，可以代替人。

　　e.g. ---- Someone is knocking at the door, Peter.---- Who is it?---- It’s me.

　　---- Who are singing?---- It is the children.

　　---- The light is still on in the lab. It must be the third-year students doing the experiment.

　　4、it與one的區(qū)別：這兩個(gè)詞都可以代表前面說過的名詞，但it用于同名同物的場(chǎng)合；one則用于同名異物的場(chǎng)合。

　　e.g. ---- Do you still have the bicycle?---- No, I have sold it.

　　---- Is this knife yours?---- No. It is Xiao Zhang’s. Mine is the one on the desk.

　　5、it與that的區(qū)別：兩詞都可代替某一特定名詞，但that指同一類，并非同一個(gè)。

　　e.g. The climate of South China is mild(溫和的); I like it very much.(it指the climate of South China)

　　The climate of South China is much better than that of Japan.(that指the climate)

　　(二)作無人稱代詞

　　it作無人稱代詞時(shí)，除了句中找不到它所代表的詞語外，另一個(gè)特點(diǎn)是它后面的內(nèi)容都是表示天氣、時(shí)間、距離、度量衡及情況等。

　　It is fine (rainy, windy, etc.).

　　It is noon.

　　It is a half hour’s walk to the factory.

　　What does it matter?

　　(三)作強(qiáng)調(diào)詞，構(gòu)成強(qiáng)調(diào)結(jié)構(gòu)

　　用以幫助改變句子結(jié)構(gòu)，使句子的某一成分受到強(qiáng)調(diào)。“It is (was) + 所強(qiáng)調(diào)的成分 + that (who) + 其它成分?！痹谶@個(gè)句型中，it本身沒有詞義。

　　(四)引導(dǎo)詞it作形式主語(賓語)

　　為了使句子平衡，常采用形式主語(或賓語)it ，而把真正的主語(或賓語)置于句子后面。通常引導(dǎo)詞it與它所代替的句子成分中間要夾有某些詞。

　　e.g. It takes half an hour to go there on foot.(It與to go there on foot之間夾有takes half an hour四個(gè)詞)

　　We thought it strange that Mr Smith did not come last night. (it與that從句中間夾有 strange)

　　但有時(shí)it與所替代部分之間并不夾有其它詞。

　　e.g. You may depend on it that they will support you.(因?yàn)榻樵~on之后一般不直接接that引導(dǎo)的賓語從句。注意：it不是多余的，不能當(dāng)作錯(cuò)句)

　　練習(xí)題

　　1. My bike is missing. I can’t find ____ anywhere.

　　A. oneB. onesC. itD. that

　　2. ---- Who’s that?---- ____ Professor Li.

　　A. That’sB. It’sC. He’sD. This’s

　　3. ---- Have you ever seen a whale alive?---- Yes, I’ve seen ____.

　　A. that B. itC. suchD. one

　　4. The color of my coat is different from ____ of yours.

　　A. thisB. thatC. itD. one

　　5. ____ will do you good to do some exercise every morning.

　　A. ItB. ThereC. ThoseD. You

　　6. We think ____ our duty to pay taxes to our government.

　　A. thatB. thisC. itsD. it

　　7. The climate of Shanghai is better than ____ of Nanjing.

　　A. thatB. itC. whichD. what

　　8. ____ four years since I joined the Army.

　　A. There wasB. There isC. It wasD. It has been

　　9. How long ____ to finish the work?

　　A. you’ll takeB. you’ll take itC. will it take youD. will take you

　　10. Mary speaks in a low voice; ____ is difficult to know what she is saying.

　　A. itB. thatC. soD. she

　　11. So ____ that no fish can live in it.

　　A. shallow is the lake B. the lake is shallow

　　C. shallow the lake is D. is the lake shallow

　　KEY:

　　1-5 CBDBA 6-11 DADC A