经典句型一 it 强调句型
it is /was 被强调部分 who/that 剩余部分(不论强调的是哪一部分，后面只能用who或that)
原句的谓语动词如果是现在或将来时态用it is....that /who 。
如果原句的谓语动词是过去时态，则用it was .....that /who 。
强调时间，地点，原因或方式时不能用when ， where ， why ， 或how ，必须用that .
经典句型二 there be 句型 表示“什么地方有.....”
there be 之后如有几个并列主语时，用单数谓语动词或用复数谓语动词要取决于第一个主语是单数还是复数。
there is a pen ， a pencil and two books on the desk .(就近原则)
there will be an important conference named the earth summit to be held here .
there have been great changes in my hometown ever since 1980s .
there must be something wrong with the cellphone.
there be 句型的其他用法。
there be 句型也可以有其他形式变化，常见的有seem to be ， happen to be ， appear to be ， used to be ， is likely to be 等。
there seems / appears to be much hope of our team winning the match .我们队似乎很有希望赢得比赛。
there are likely to be more difficulties than expected while carrying out the experiment .
the thief broke in ， to his delight ， there happened to be nobody in the room .
there be 句型中的be 动词，也可以替换成其他动词，常见的有live ， remain ， come ， stand ， lie ， occur ， exist ， follow 等。
once there lived many dinosaurs here millions and millions of years ago .
there stand many skyscrapers (摩天大楼)in the modern city .
there lies a railway in our city .
there came a time when ，ost of people demanded for freedom and equality .
there exist serious issues in the world and we should take action to solve them before it is too late .
there be 句型的独立主格形式作状语
there being no time left ， we must hurry .
=because there was no time left ， we must hurry . 没剩多少时间了，我们必须抓紧。
there having been no rain for a long time ， the crops in the field died .
=because there had been no rain for a long time ， the crops in the field died . 久旱无雨，地里的庄稼都死了。
有连词时用句子，没有连词时用there be 独立主格形式作状语.