Grammar and usage To-infinitiveFigure out the meanings of the proverbs and the usage of the underlined part.• To know everything is to know nothing. • It is easier to get money than to keep it.• Eat to live, but not live to eat.什么都知道一如什么都不知道。挣钱容易，攒钱难。吃饭是为了生活，但活着不是为了吃饭。I. The to-infinitive can be1. subject of a sentence• To see is to believe. 百闻不如一见。• 了解英语是一回事， 会英语是另一回事。__________ something about English is one thing; __________ English is quite another.• 先制定个计划是个好主意。 ________ a plan first is a good idea.To knowto knowTo make• 学好英语很难。________________ is difficult.= It is difficult ______________.• 再见到你真高兴。It’s a great pleasure to see you again.To study English wellto study English wellTip:• 动词不定式和不定式短语做主语时，常用 it 做形式主语，其句型结构为： It is + 形容词或名词（或词组） + 不定式短语…。• 这时的形容词常为 easy, difficult, hard, good, useful, wrong, right, necessary, impossible, important 等。名词或词组常为 a fact, a great day, a great thing, a pity 等。• 如要说明动词不定式的动作的执行者，可在不定式前加一个介词 for 引导的短语，其句型结构为： It is + 形容词 +for sb +不定式短语。如：• Mr White thinks that it is right for rich people to help poor people.• 但如果表语是 kind, nice, clever, wise, foolish, careless 等描述动作执行者的性格品质的形容词时 , 则应在不定式前加一个 of 引导的短语 , 而不用 for, 句型结构为 : It is + 形容词 + of sb. + 不定式短语。如：• It’s kind of you to help me with my math.• 固定结构 It takes/took sb. some time to do sth….( 做某事花费某人多少时间 ) 。如：• 他花了 5 个月的时间学开车。 It took him five months to learn to drive.• 动词不定式还可以和 what, where, how, when, which 等连接代词（副词）连用，...
