1、To take an umbrella when you out is necessary for you.所以,上面的句子可以改写为:It is necessary for you to take an umbrella when you go out.形容词修饰动词不定式描述的动作,即 to take an umbrella is necessary。例如:Its very necessary for us to master a forengn language.(掌握一门外语对我们来说是很有必要的。)2.作宾语(1) 类似的动词(后面跟不定式)还有哪些?(2) it 充当形式宾语,真正
2、的宾语(to do 不定式)后置,以避免头重脚轻。I think it necessary for you to learn from others.I think it important to be an honset man .(我认为做一个诚实的人很重要)常见的动词有 think, feel, make, find, consider, count, deem, judge, believe, take 等。think/feel/make/find/consider/believe it + adj. + (for sb.) to do sth.3.作表语(1) 观察例句,思考不定式的
3、位置和作用。Her wish was to become a teacher.不定式的位置: 系动词之后不定式的作用:充当表语My job is to take care of patients in the hospital(我的工作是照顾医院里的病人)(2) 注意:除 be 动词之外,还有其它系动词有类似的用法。如:a. 他似乎是住在这个地区。He seems to be living in the area.b. 他似乎是伤风了。He seems to have/get a cold.4.作补语(1) 这类及物动词常见的有:需要省略 to 的情况类似用法的动词有:The peliceme
4、n saw that man open the window(警察看见那个人打开了窗户)被动语态中,被省略掉的 to 必须还原。5.作定语(后置)不定式 to drink 修饰something,作定语,放在所修饰的词后面。例如:I have a wife and a son to look after.(我有妻子和一个儿子要照顾)6.作状语(1)做目的状语(可位于句末或句首)I work out to lose weight(我锻炼是为了减肥)(2)做结果状语1.too.to 太.而不能.He is too sick to go to work(他的病严重到不能去上班)2.adj+enough+to do 足够.能够.Our money is not enough to buy a new car(我们的钱不够买一辆新车)