什么叫to be句型?

不定式的定义
动词不定式的概念：动词不定式指由to 加上动词原形（而且只能是动词原形）所构成的一种非限定性动词,但在有些情况下to可以省略.动词不定式在语法功能上可作主语 、宾语、表语、定语和状语.动词不定式的构成与形式：动词不定式可以作以上各种成分,但它毕竟是动词,所以有动词的属性.动词不定式及其短语还可以有自己的宾语、状语,虽然动词不定式在语法上没有表面上的直接主语,但它表达的意义是动作,这一动作一定由使动者发出.这一使动者我们称之为 逻辑主语,其形式如下：主动形式 被动形式 一般式 （not） to make （not） to be made 完成式 （not） to have made （not） to have been made 进行式 （not） to be making 完成进行式 （not） to have been making 1) 现在时：一般现在时表示的动词,有时与谓语动词表示的动作同时发生,有时发生在谓语动词的动作之后.He seems to know this.I hope to see you again.= I hope that I'll see you again.我希望再见到你.2) 完成时：表示的动作发生在谓语动词表示的动作之前.I'm sorry to have given you so much trouble.He seems to have caught a cold.3) 进行时：表示动作正在进行,与谓语动词表示的动作同时发生.He seems to be eating something.4) 完成进行时：She is known to have been wreaking on the problem for many years.
[编辑本段]一、作宾语
1) 动词+ 不定式 afford aim appear agree arrange ask be decide bother care choose come dare demand desire determine expect elect endeavor hope fail happen help hesitate learn long mean manage offer ought plan prepare pretend promise refuse seem tend wait wish undertake 举例：The driver failed to see the other car in time.司机没能及时看见另一辆车.I happen to know the answer to your question.我碰巧知道你那道问题的答案.2）动词+不定式 ；动词+宾语+不定式 ask,beg,choose,expect ,hate,help intend like,love,need prefer,prepare,promise,want,wish… I like to keep everything tidy.我喜欢每件东西都保持整洁.I like you to keep everything tidy.我喜欢你能使每件东西都保持整洁.I want to speak to Tom.我想和汤姆谈话.I want you to speak to Tom.我想让你和汤姆谈话.3） 动词+疑问词+ to decide,know,consider forget,learn,remember,show,understand,see,wonder,hear,find out,explain,tell Please show us how to do that.请演示给我们如何去做.There are so many kinds of tape-recorders on sale that I can't make up my mind which to buy.有这么多的录音机,我都拿不定主意买哪一种.注意:疑问词带不定式在句中作成分时,谓语动词用单数.The question is how to put it into practice.问题是怎样把它付诸实施.