51.used to, supposed to.不能省略 d。

F:I use to enjoy gardening.
T:I used to enjoy gardening.
F:My uncle has trouble breathing: he isn't suppose to smoke.
T:My uncle has trouble breathing: he isn't supposed to smoke,

52.very.不能用此词来代替too。

F:This book is .very old to use anymore.
T:This book is too old to use anymore.
F:The weather is very cold to go swimming.
T:The weather is too cold to go swimming.
F:The actor is very nervous to go on stage.
T:The actor is too nervous to go on stage.

53.wait on意为serve, 不要与 wait for混淆。

F:My friend was late; I had to wait on him for half an hour.
T:My friend was late; 1 had to wait for him for half an hour.
F:Good clerks are happy to wait for their customers.
T:Good clerks are happy to wait on their customers.

54.want 后面不跟名词从句,而跟不定式。

F:She wants that she can pass the test.
T:She wants to pass the test.
F:My father wants that I do well in school.
T:My father wants me to do well in school.

55.where 指地点,避免where用作that的同义词。

F: I read in the newspaper where crime is on the increase.
T: I read in the newspaper that crime is on the increase.
F: Have you noticed where people are smoking less than they used to?
T:Have you noticed that people are smoking less than they used to?

56.which 是关系代词, 指物, 从不指人。

F:The person with which I had the argument was the chair-man.
T:The person with whom I had the argument was the chair-man.
F:The scientist which invented the electric light was Thomas Edison.
T:The scientist who invented the electric light was Thomas Edison.
F:I was annoyed by the salesman which came to my door.
T:I was annoyed by the salesman who came to my door.

57.while通常指时间,避免用while表示对比。

F:While my family is not rich, we have many advan-tages.
T:Although my family is not rich, we have many advantages.
F:While I was not busy, I couldn't help him.
T:Although I was not busy, I couldn't help him.
F:While teaching seems like a good profession. I would prefer to be a lawyer.
T:Although teaching seems like a good profession, I would prefer to be a lawyer.

58.who,whom.Who是代词主格,whom是代词宾格。

F:Who did you speak to about your problem?
T:Whom did you speak to about your problem? (Whom is the object of the preposition to.)
F:Whom did you say ruled the country at that time?
T:Who did you say ruled the country at that time? (Who is the subject of the verb ruled.)
F:John Kennedy was a man who many people admired.
T:John Kennedy was a man whom many people admired.(Whom is the object of the verb admired.)

59.who's,whose.Who's意为who is;Whose则表示所属。

F:The counselor was the person who's advice I took.
T:The counselor was the person whose advice I took.
F:Do you remember whose in charge of preparing the menu?
T:Do you remember who's in charge of preparing the menu?

60.would尽管此词是will的过去式,但常常用来表示现在发生的动作，同时也经常在主要为过去式的名词从句中。

F:Will you like a cup of coffee now?
T:Would you like a cup of coffee now?
F:I have never met your parents, but I will like to know them.
T:I have never met your parents, but I would like to know them.
F:My boss told me that he will increase my salasy next year.
T:My boss told me that he would increase my salary next year.
F:We heard on the radio that it will rain tomorrow.
T:We heard on the radio that it would rain tomorrow.