1、Unit2 Healthy Lifestyle MENULeading-inWhile-classAfter-classPart.1 Leading-inPart.1 Leading-inLeading in阅读活动1所给的其他句子，讨论并归纳斜体部分（不定式）在句子中的功能。1 To change bad habits is never easy.2 It took the surgeon three hours to finish my mothers lung surgery.3 To join the Peoples Liberation Army, it is required fo
2、r men to shave off their beards.4 It was not polite to disturb your neighbours with loud music last night.Leading in四个句子中的不定式都充当主语主语。用形式主语It代替真正的主语 to change bad habits符合英语表达习惯，避免句子头重脚轻、结构失衡。如果作者有意将比较长的不定式主语放在句首，那么作者就是想要突出不定式的内容。Part.2 While-classPart.2 While-classWhile-class再次阅读 Reading and Thinkin
3、g板块中的语篇，找出所有含有不定式作主语的句子与同伴讨论答案。However, during this period, it can be easy for some of them to form bad habits.To prevent harmful habits like these from dominating a teenagers life is essential.To change bad habits is never easy, even with many attempts.After all, it is not easy to break bad habits.
4、While-class动词不定式（短语）作主语动词不定式（短语）作主语时，一般表示具体的、个别的、次性的或具有将来意味的动作，作主语时，谓语动词通常用单数形式，具体用法如下：1.用作主语的动词不定式（短语）常出现在谓语动词之后，这时需在句首用形式主语It指代它。其句型有2种：（1）It+v.+宾语/表语（+ for sb.）+ to do sth当表语为名词或为描述动词不定式（短语）所表示的动作的特征的形容词时，用for引出动词不定式（短语）的逻辑主语。这类形容词有 difficult，easy，hard，important，interesting等。While-class例：It takes
5、 three generations to make a gentleman.谚十年树木，百年树人。（It+v.+名词短语+ to do sth.）It is hard task to break up long habit in a short time.谚旧习难改。（It+be+名词短语+ to do sth.）It was easy to imagine the danger ahead of them.很容易想象他们前面的危险。（It+be+形容词+ to do sth.）It is against my principles to do such a thing.做这样的事违背我的原
6、则。（It+be+介词短语+ to do sth.）What a relief it is for us to succeed in our experiment at last！我们的实验终于成功了，这对我们真是一个极大的安慰！（it+be+名词短语+ for sb.+ to do sth.）It was hard for him to live on his small income.依靠他那点工资维持生活很难。（It+be+形容词+ for sb.+ to do sth.）While-class（2）It+v.+表语+of sb.+ to do sth.（表语常为表示人的性格、品质的形容
7、词，如good，kind，nice，foolish，polite，ever，careless等。）例：It was careless of you to leave your umbrella on the train.你真粗心，把伞忘在火车上。While-class2.动词不定式（短语）作主语可位于句首。例：To do this is to cut the foot to fit the shoe.这样做是削足适履。While-class3.疑问词+动词不定式（短语）结构动词不定式（短语）可与疑问词when、where、how、what、which、who等组合，在句中作主语。例：Where
8、 to hold the meeting is still unknown.会议地点还未知。How to solve the problem has not been decided yet.如何解决这个问题还未决定。While-class will take/ nutrition specialist/ a balanced diet menu/ make an hour /for you useful/ turn to fitness consultant/ for advice illegal/ dangerous/ take / drugs harmful/skip breakfast
9、 /often It is useful to turn to a fitness consultant for advice. It is dangerous to take drugs illegally.It is harmful to often skip breakfast.Part.3 After-classPart.3 After-classWhile-class1 A: Hello, doctor. I want to lose weight, but I just cant seem to do it. What can you do to help me?B: Well,
10、first, its necessary to what you eat. Cut out all fatty food and sugary drinks, and eat more fruit and vegetables2 A: I really need to a way to exercise more. I could use a fitness app, but my phones full. B: So delete a few files. Im sure the app doesnt take up much space.While-class3 A: Before exe
11、rcising, always do a few warm-ups to .B: I know. But then I always feel too tired to continue!4 A: Should I go for the pizza or the fried chicken? I hate like these. You know whatIm going to eat both！B: Wow! Dont eat too much junk foodyoull get fat. Ive actually to go on diet, so Ill just stick to t
12、he fruit salad.Summary动词不定式（短语）作主语动词不定式（短语）作主语时，一般表示具体的、个别的、次性的或具有将来意味的动作，作主语时，谓语动词通常用单数形式，具体用法如下：1.用作主语的动词不定式（短语）常出现在谓语动词之后，这时需在句首用形式主语It指代它。其句型有2种：（1）It+v.+宾语/表语（+ for sb.）+ to do sth当表语为名词或为描述动词不定式（短语）所表示的动作的特征的形容词时，用for引出动词不定式（短语）的逻辑主语。这类形容词有 difficult，easy，hard，important，interesting等。（2）It+v.+表语+of sb.+ to do sth.（表语常为表示人的性格、品质的形容词，如good，kind，nice，foolish，polite，ever，careless等。）2.动词不定式（短语）作主语可位于句首。3.疑问词+动词不定式（短语）结构动词不定式（短语）可与疑问词when、where、how、what、which、who等组合，在句中作主语。Thank you!
