it 与there be的用法
I have anew pen. It is beautiful.
The Brownshave a new baby. It's cute.
It'stwelve o'clock now.
It's nogood telling him that.
It'snecessary for you to do so.
(4)用在强调结构中，构成强调句式：It is/was +被强调部分+that/who/whom +句子其余部分，可强调除谓语以外的句子其他成分，如，
It wasthis morning that I saw him in the street.
It was Iwho saw him in the street this morning.
It was inthe street that I saw him this morning.
It was himwhom I saw in the street this morning.
There area lot of students playing on the ground.
There isgoing to be a test this afternoon.
There is apen and three pencils in the pencil-box.
Thereisn't a desk， a bench and three chairs in the room.
There arelots of people like it， aren't there？
there be句型，谓语动词除be之外，还可用其他表示存在，位置移动等意义的不及物动词或词组，如exist， stand， lie， enter， come， happen to be，appear to be等，如，
Therestands a house at the foot of the hill.
there be句型表示“存在”而have表“有”、“拥有”，所以there be中be不能换成have，但当have表示事物的特征时，可用“主语+have”结构替换there be 句型，如：
There arefive doors in the house.
The househas five doors.
there be 的其它句型：
1、There must be a meeting in the office.
2、There have been great changes since 1979.
3、There being no bus， we had to walk home.
例1____that he went to sleep.
A It wasuntil midnight B That was until midnight
C It wasnot until midnight D That was not until midnight
解析：该题答案为C。强调until结构时，要将否定词not移到until前。又如：He didn't leave until twelve 改为It was notuntil twelve that he left.
例2Thereare a lot of students ____ in the class room.
A talk Btalking C talked D to talk
解析：该题正确答案为B。There be句型为倒装句，可换为A lot of students aretalking in the class room. 又如：There is a lot of noiseheard out in the street.