4. expensive/ high/ cheap/ low 　　 这四个词在谈论到价格的高低时，要注意使用。expensive与high涉及到价格"高"，而cheap 与low涉及到价格"低"。 　 (1) expensive昂贵的，花钱多的。这个单词若谈到"价格高，货贵"时，其主语不能是价格，必须是货物、物品本身。如： 　 This watch is expensive. 这只表很贵。 　 These glass-products are not expensive. 这些玻璃制品不是很值钱。

注意：cheap表示"价廉"，"便宜的"，其主语也不能是价格，必须是物品本身。如： The cheap table was bought from him. 这张便宜的桌子是他卖给我们的。 This cloth doll is very cheap. 这只布娃娃很便宜。

(2)high在表示价格时，含义是"高"，low在表示价格时，含义是"低"，这两个词不能用于物品本身，只

能用在价格上。如： The price of this watch is very high. 这只表的价格太高了。 The price of this book is not low for me. 这本书的价格对我来说是不低。

下面我们试看几个句子的正误对照： The price of this computer is expensive. (宜改为：This computer is expensive. 或The price of this computer is high. ) The price of this pen is not cheap for him to buy. (宜改为：This pen is not cheap for him to buy. 或 The price of this pen is not low for him. )

3. cost/ take/ spend/ pay (1) cost表示"花钱"，花费，付出(只能用于钱、精力、生命等；主语必须是物。) 　 The book cost me five yuan.

(2) take的主语是动词不定式, 通常用it做形式主语。 It took me five yuan to buy the book..

(3) spend，在主动语句中主语是人 I spent five yuan on (for) the book.或I spent five yuan (in) buying the book.

(4) pay的主语是人。 I paid five yuan for the book.

2. big/ large/ great

上述形容词都表示"大"，但侧重点及程度不同。 　 (1) big指具体事物的大小，强调比正常形体的标准大，既可用在普通场合， 也可用在正式场合。它可用来指人的身材高大或"长大了"，还可表示"伟大"，"重要"之意。如：

Can you lift up this big stone? On the last day I made a big decision.

(2) large特别强调远远超过标准的大，指体积、面积、容积、数量之大。如： A whale is a large animal. A large crowd collected at the gate of the theatre.

(3) great除了表示数量体积之大外，又指抽象的程度，意味着伟大性，重要性， 优越性；常用于抽象

或无形的东西；用于有形的东西时，常带有"伟大"，"大得令人吃惊"等意思，含有一定的感情色彩。如： China is a great country with a long history.

He was one of the greatest scientists.

1. think/ think/about/ think of (1) think 单独使用时表示"思考"， 接that 宾语从句时意为"认为"，"觉得"。 　 I am thinking how to work out the problem. 　 I think she is a good student.

当宾语从句含有否定概念时，通常形式上否定think ，但意义上却是否定宾语从句。

I don't think he can come. I don't think it will be windy.

(2)think about 可接一个名词，动词-ing 形式或由疑问词引导的不定式或宾语从句，意思是"考虑……"。

I have thought about it for a long time. Please think about how to tell her the bad news.

(3)think of 表示"认为"， 一般用于疑问句中，与what 连用。 　　 What do you think of the TV play? = How do you like the TV play?

4. 定语从句

[名师讲解]

3. 动词不定式

2. 过去完成时

1. 过去将来时

35. ---There is a little traffic accident． 36. ---There's a big traffic jam. 37. ---Well, I'm sure he'll be here before long. 38. ---I'm beginning to get angry with him! 39.---Yes, we can't wait any longer. Let's go without him. 40. ---That's terrible! 41. ---That's a really bad excuse! IV. 重要语法

34. ---Come down, Polly!