A doctor for animals

　　此外，as if （as though）后可以跟动词不定式。如：

　　She raised her hand as though （as if） to hang the picture on the wall. 她举手象要把这幅画挂在墙上。

　　He raised his hand as though to take off his hat. 他举起手来，像要脱帽似的。

　　2. She tried hard to reach the baby’s room… but the house broke in two, dropping her to the first floor and leaving the baby’s bed hanging in the edge of the two-story house. 他尽力地到达婴儿房间，但是房子裂成了两半，把她摔到了楼下，而婴儿的小床留在上面，搭在这座二层楼的边缘上，摇摇欲坠。

　　由dropping 和leaving 组成的两个-ing形式短语在句中作伴随情况状语。如：

　　They came into the room laughing and talking. 他们说说笑笑地走进屋来。

　　Taking a dictionary, she began to prepare her lessons. 她拿了本词典，开始准备功课。

　　3. …… just as the bed crashed to the first floor ……与此同时床坠落到了一楼。

　　4. It is true to say a dog is man’s best friend or at least Roberts best friend. 事实上说狗是人类最好的朋友，起码是罗特的最好的朋友。

　　* 句中it是形式主语，to say a dog动词不定式是真实主语。

　　句中it作先行代词用。It在句中充当形式主语或形式宾语，而将真正的和逻辑上的主语或宾语（通常用不定式短语、动名词短语或从句表示）移到后面去。如：

　　It is very important for us to learn English. （it代替不定式to learn English做形式主语）我们学习英语是十分重要的。

　　It takes much time to carry out a test. （it 代替不定式to carry out a test作形式主语）进行试验是要花费许多时间的。

　　it 作形式宾语：在具有宾语补语的句子里，it在动词后作直接宾语的先行代词，在宾语补语后面再出现真正的直接宾语（一般以不定式短语、动名词短语表示，但也有用that引出一个宾语从句）。如：

　　I found it a bit difficult to work in class because I kept on thinking about, the match in the afternoon. 我发现在课堂上学习有点儿难，因为我一直在想着下午的比赛。

　　We think it useful to learn the computer well. 我们认为学好计算机是有用的。

　　* at least 意思是“至少，起码”。如：

　　At least I can give you ten dollars. 最少我能给你十美元。

　　at least 的反义词是at most 意思是“至多”。

　　I can pay only fifty dollars at most. 我最多只能付五十美元。

语法讲解The Infinitive

动词不定式（三）

用作主语

　　To do the job well is not easy. 做好这工作不容易。

　　To drive fast is dangerous. 开快车是危险的。

　　To learn English well is very important．学好英语是很重要的。

　　在现代英语中，更为普遍的是用it 来开始一个句子，作形式主语，而把真正的主语动词不定式（或短语）放在后面。例如：

　　It’s not easy to learn a foreign language well. 学好一门外语不容易。

　　It is necessary to make a plan for this course of study．必须制定一个学习这门课程的计划。

　　It’s better to give than to receive. 奉献总比索取好。

　　如果要说明不定式表示的动作是谁做的，可以在不定式前加一个for 引起的短语：

　　It is not hard for one to do a bit of good. 对于一个人来说做点好事并不难。

　　在以某些形容词（如: kind ,good ,nice ,clever, wrong, right ,foolish, wise, unwise等）作表语时，不定式前常可加一个of引起的短语，来说明不定式指的是谁的情况，如：

　　It’s kind of you to think so much of us. 你总是想着我们真是太好了。

例句：

　　To make a mistake is human. 犯错误是人之常情。

　　It’s better to be the safe side. 万无一失更好。

　　To speak well ……/ ill of everyone……说人好（坏）话……

　　To work hard is the key to success. 勤奋学习是成功的钥匙。

Lesson 57 教学设计示例

Properties: Recorder, Overhead Projector

Teaching Objectives:

　　1. Understand the dialogue.

　　2. Learn some useful structures and phrases.

　　3. Learn the grammar: the Infinitive.

Language focus: like being a… , play with, a lot of fun

Teaching Procedures:

I. Showing the teaching aims

II. Revision

　　Revise the names of animals that could be kept as pets: dog, cat, snake, parrot, rabbit, fish, etc. Ask Does anyone have a pet? wWhat kinds of animals would you like to have as pets?

III. Leading in

　　Ask: What do you want to be when you grow up? Let the students discuss the question. Then give the second question: What do you want to be, a doctor for humans or a doctor for animals? Why?

IV. Presentation

　　Look at the picture in Lesson 57. The boy is sitting on the sofa. His father is talking with a dog in his hand. What did they say? Play the tape for the students to listen, check the answers with the students. Then read the dialogue and answer the questions of Exercise 1 in the workbook in pairs. Go through the dialogue and explain some language points.

　　Play the tape for the students to listen and repeat, ask the students to practise. Then let them act out the dialogue in pairs.

VI. Free practice

　　Do an example with one student. Then let the class make up their own dialogues in pairs. Get them to act out their dialogues. Ask the students to discuss the questions. Ask:

　　Do you think it's more important to help people than animals? Why?

　　What kinds of jobs do you know?