C
call
［误］ I'll call at Mr Brown.
［正］ I'll call on Mr Brown.
［误］ I'll call on Mr Brown's home.
［正］ I'll call at Mr Brown's home.
［析］ 作"拜访"讲时，at后面接访问地点，而on后面接访问的人。
call on drop in visit
call on比较正式的为公务的访问，如：We were called on by the old students. 而drop in则是比较随便的走走，顺便拜访，如：If you're free, drop in. 而visit则是更正式的外交访问或友好往来，如：My school's headmaster will visit America next week.
can
［误］ A blind man can not judge colours.
［正］ A blind man cannot judge colours.
［误］ I cann't call for you at ten.
［正］ I can't call for you at ten.
［析］ can的否定形式应为cannot或can't.
［误］ It's only six o'clock. That mustn't be the postman.
［正］ It's only six o'clock. That can't be the postman.
［析］ must用来表示一种肯定的推断，如：She must have some problems. She keeps crying. 但在否定句中则要用can't， 要表示对过去的推测则要用"must+have+过去分词"的表达法，如：The lights have gone out.A fuse must have blown.而对过去的否定推测则多用"can't+have+过去分词"，如：I don't think he can have heard you. Call again.
［误］ We could not help to laugh at once.
［正］ We could not help laughing at once.
［正］ We could not help but laugh at once.
［析］ "couldn't help+动名词"表示禁不住做了某事。但could not help but与could not but后面要加不带to的不定式，意思都是不得不去做某事.如：You could not (help) but respect him.
can be able to
can与be able to都可以用来表示能力，但can只有现在时与过去时，be able to则可用任何时态，如：He will be able to teach the child. 但要表示经过努力而达到的一次性动作则只能用be able to，如：He finally was able to jump over 210 meters. 或：The plane was able to fly over the mountain. 但要注意的是这两个词都没有进行时态，而be able to后面不接不定式的被动态。
can could
can与could都可以用在现在时的口语中，只是用could更为礼貌，语气更委婉。如：Could you tell us a story?
care
［误］ I don't care coffee.
［正］ I don't care for coffee.
［误］ Take care for your steps.
［正］ Take care of your steps.
［析］ care for是"对某物感兴趣"，而care of是"关心，要当心某事"，如：She didn't care for him. Take care of what you are doing.
［误］ I don't care where we will go if it doesn't rain.
［正］ I don't care where we go if it doesn't rain.
［析］ 在it doesn't matter, I don't care, I don't mind, 及in case引出的状语从句后面要用现在时表示将来。如：I've got a football in case we have time for a game.
change
［误］ I want to change my camera with that one.
［正］ I want to change my camera for that one.
［析］ change for为"以某物为交换物"。而change with则是"随……而变"，如：The wood's colour changed with the season.
cheap
［误］ A teacher's salary is generally very cheap.
［正］ A teacher's salary is generally very low.
［析］ 工资的高低要用low，cheap是指价格便宜，如果要讲物美价廉则要用not expensive, 如：This car is not expensive.
choose
［误］ We each had to have a choose of A or B.
［正］ We each had to have a choice of A or B.
［析］ choice是名词，而choose是动词。
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