1.替代词one, ones, that, those, it, this, that That替换单数可数名词或不可数名词；one只替换单数的可数名词。 Eg: The vase on the left is more beautiful than __________ on the right. the one The coffee produced in Brazil is more famous than __________in Mexico. that  

That只用于替换表示事物的名词， 而one/ones替换表示人和表示事物的名词皆可。 Eg: His younger sister is taller than the elder ___. I need the plastic bags, not the paper______ . ones

That/ those一般不带前置定语，但必须有后置定语。One/ones都可。当替换词的后置定语用所有格的of短语或当替换词被所有格修饰时，不用one/ones而用that of/those of. Eg: I like the vase better than ________________in another shop. the one / that The windows of your flat are cleaner than _________of mine. those   A grandparent’s job is easier than ________of a parent. that The computers in our school are connected to the Internet while __________ in their school aren’t. those

That/ those用于替换有定冠词的名词；one/ones用于替换有不定冠词的名词。 Eg: The style of the building is similar to _________of a temple. that A CD player made in Japan costs more than ________made in China. one

2. It和one   It用以指特定的前面提到过的事物，即：it和它替换的是同一个事物，it前无修饰语；而one用于替换与前提事物有共同之处但并不完全一样的事物，因此，one之前或之后一定有修饰语来加以区别。 Eg: I bought a dictionary three years ago and I am still using______ now. I bought a dictionary three years ago but I am going to buy a new _______soon. it one

It引起的几个易混淆的时间句型 It + be + 时间 + since-clause 这个句型表示从since 从句谓语动作发生以后到现在或过去所经过的一段时间，意为“自从......以来已多久了” It is three years since his father passed away . It + be + 时间 + before-clause 这个句型中的时间一般为表示一段时间的词语 (如：a long time , months , weeks , days ,hours , minutes ) ，主句中的谓语动词用肯定式，意为“过多长时间才......”。主句的谓语动词是否定式时，意为“没过多长时间就......”。主句的时态可用过去时was或将来时will be；用was 时，before从句的动词用一般过去时；用will be 时，before从句常用一般现在时。

她没过多久就背会了那些诗歌。 It was _______________she learned those poems by heart . 过了很久警察才来。 It was ______________the police arrived .   要过好几个小时他才会作出决定。 It __________hours before he makes a decision . 要不了几个小时我们还会再见面的。  __________________before meet again . not long before long before will be It will not be hours

 3. It + be + 时间 + when-clause 这个句型中, it 指时间，而且表示时间的词语前没有介词(时间一般为具体时间)。主句中的谓语动词和从句中的谓语动词在时态上一般是一致的，主句是will be，when从句用一般现在时代替将来时。 It was already 8 o‘clock when we got home . It was the next morning when we finished our work . It will be midnight when they get there .

It + be + 时间 + that-clause 这个句型是个强调句型。例如：  It was two years ago that he made an important invention .  (原句是：__________________________________) It was at 5 o’clock that he practised playing the violin in the morning .  (原句是：________________________________)  比较：It was 5 o’clock when he started in the morning . (5 o‘clock前没有介词，这是个定语从句) He made an important invention two years ago . He practised playing the violin at 5 o‘clock in the morning .

It + be + time + that-clause 这个句型属虚拟语气结构，不管主句中用的是 is 或 was ，that从句都须用动词的过去式或should + 动词原型(但不及用过去式普通)，在time之前有时可加上high或about 以加强语气。例如：  It is time(that)we handed in our exercises . (= It is time that we should hand in our exercises .)  It is high time (that ) she wrote a letter to her boyfriend .

It / This / That + the first(second , third …) time + that-clause 这个句型表示截止到说话时为止的某人的一种经历，关键是注意time前有序数词，主句是 is 时 ，从句要用现在完成时；如果主句用一般过去时was ，则从句须相应地用过去完成时。例如：  This is the first time (that) these Europeans ____________the Great Wall .  It was the fifth time (that) I ___________a friendly visit to Africa . have visited had paid

It 用于强调句 结构：It+动词be+强调部分+who(whom)/that+其他部分it可以用来对句子的某一成分加以强调。 Eg: Nancy saw your sister in Tokyo last week. It was Nancy who saw your sister in Tokyo last week. It was your sister whom Nancy saw in Tokyo last week. It was in Tokyo that Nancy saw your sister last week.

It was last week that Nancy saw your sister in Tokyo. 有些否定句也可以改成这种强调结构： It wasn’t until last summer that I heard from her. I didn’t do all this for myself. It wasn’t for myself that I did all this. 问句也可变成这种结构： Who called him “comrade”? Who was it that called him “comrade”?

How did you forget to lock the door? How was it that you forgot to lock the door?

Ex:把下列句子改为强调句： 1.Tom broke the window last night. 2. They want money. 3. Peter saw his friend in the park yesterday. 4. I didn’t have an opportunity of seeing her again for several years. 5. Why does everyone think I’m narrow-minded? 6. I didn’t receive my letter until yesterday? 7. Did Dick call the meeting last week? 8. Did it happen in 1980?

As ___ happens , I have brought my umbrella with me . Tom‘s mother kept telling him that he should work harder , but ___ didn’t help . A. he B. which C. she D. it As ___ happens , I have brought my umbrella with me .  A. it B. this C. that D. such  3. ___has already been pointed out , grammar is not a set of dead rules .  A. As B. It C. That D. This  4. It was seven forty-five ___he finished the work .  A. when B. that C. when D. before D A   A A

5. Was it because it snowed last night ___ he didn‘t come ?  A. why B. that C. when D. which  6. Does ___ matter if he can’t finish the job on time ?  A. this B. that C. he D. it 7. European football is played in 80 countries , making ___ the most popular sport in the world .  which B. this C. that D. it 8.___ is no doubt that he will succeed in his experiment .   A. It B. This C. That D. There B D D D

9. It worried a bit ___ her hair was turning gray .  A. while B. that C. if D. for 10. It was not ___ she took off her dark glasses I realized she was a famous film star .  A. when ; that B. until ; that C. until ; when D. when ; then  B B