31.little,a little.Little意为not much.A little意为some.

F:He has had difficulty in finding a job because he has a ==little education.
T: He has had difficulty in finding a job because he has ==little education.
F:This machine is easy to operate; you need a little skill.
T:This machine is easy to operate; you need little skill.
F:Learning to ski is difficult; little effort is required.
T:Learning to ski is difficult; a little effort is required.
F:Please give me little more time to finish writing.
T:Please give me a little more time to finish writing,

32.like,as, as if.Like 是介词;as, as if(或 as though) As做in the capacity of解时也是介词。

F:She doesn't study like she should.
T:She doesn't study as _she should.
F:You ought to write as me.
T:You ought to write like me.
F:Like the coach said, the team performed well.
T:As the coach said, the team performed well.
F:She acts like she doesn't understand.
T:She acts as if (or as though) She doesn't understand.
F:Like a full-time student, you must register for at least four courses a semester.
T:As a full-time student, you must register for at least four courses a semester.

33.lose,loose.Lose是动词,其过去式为lost.Loose是形容词,意为not tight。

F:She will loose weight if she goes on a diet.
T:She will lose weight if she goes on a diet.
F:One of the knobs on the drawer is lose.
T:One of the knobs on the drawer is loose, (meaning "not tight")
OR
One of the knobs on the drawer is lost, (meaning "missing")

34.maybe,may be.Maybe意为perhaps;May be是动词。

F:May be the sun will come out tomorrow.
T:Maybe the sun will come out tomorrow.
F:The secretary maybe out to lunch.
T:The secretary may be out to lunch.

35.myself,himself,herself,yourself,ourselves, themselves,和yourselves是反身代词,用于动词的主语同时接受该动词的动作时,或用为强调。

F:Only Bill and myself witnessed the accident.
T:Only Bill and I witnessed the accident.
F:The tires of the car are bad, but itself is in good  condition.
T:The tires of the car are bad, but the car itself is in good  con-dition.
F:They did the work by theirselves.
T:They did the work by  themselves.
F:The little boy was extremely intelligent; he taught him to  read.
T:The little boy was extremely intelligent; he taught himself  to read.

36.passed,past.Passed是pass的过去式,Past既可作形容词也可做名词。

F:When I asked, she past me the sugar.
T:When I asked, she passed me the sugar.
F:I past his house on the way to the post office.
T:I passed his house on the way to the post office.
F:In passed times, salt was often used as money.
T:In past times, salt was often used as money.
F:One can learn from passed experiences.
T:One can learn from past experiences.
OR
One can learn from experiences in his past.

37.percentage,percent,percent跟在数字之后

F:A large percent of his salary is spent on food.
T:A large percentage of his salary is spent on food.
F:Almost fifty percentage of our energy resources come from abroad.
T:Almost fifty percent of our energy resources come from abroad.

38.prefer和superior后面不跟介词than。

F:Many students prefer history than mathematics.
T:Many students prefer history to mathematics.
OR
Many students prefer history rather than mathematics.
F:I believe that a microwave oven is superior than a conventional oven.
T:I believe that a microwave oven is superior to a conventional oven.

38.principal,principle.Principal可作名词或形容词,意为 chief official or main.Principle仅作名词,意为fun-damental truth 。

F:In his research he followed basic scientific principals.
T:In his research he followed basic scientific principles.
F:The principle side effect of decongestants is drowsiness.
T:The principal side effect of decongestants is drowsiness.
F:The chairman pointed out his principle objections.
T:The chairman pointed out his principal objections.

39.quiet,quite.Quiet意为silent.Quite意为completely。

F:We must be quite inside the library.
T:We must be quiet inside the library.
F:Your answer was quiet wrong.
T:Your answer was quite wrong.