40.raise,rise,rise不带宾语;raise带宾语。

F:He rose his hand before asking a question.
T:He raised his hand before asking a question, (past tense)
F:Having finished lunch, he raised from the table.
T:Having finished lunch, he rose from the table, (past tense)
F:The sun is raising high in the sky.
T:The sun is rising high in the sky. (present participle)
F:Some questions were risen about taxes.
T:Some questions were raised about taxes, (past participle)
F:My grandfather raises early every morning.
T:My grandfather rises early every morning, (present tense)
F:Private income has raised steadily for the past decade.
T:Private income has risen steadily for the past decade. (past participle).

41.reason...because为误用,应说reason...that。

F:The reason he makes poor grades is because he never studies.
T:The reason he makes poor grades is that he never studies.
F:My reason for using a typewriter is because my handwriting is poor.
T:My reason for using a typewriter is that my handwriting is poor.

42.seldom ever,seldom or ever为误用,应说seldom if ever或hardly ever.

F:Tigers seldom ever eat human beings.
T:Tigers seldom if ever (or hardly ever) eat human beings.

43.some,somewhat.Some是形容词;some what是副词。

F:Students find that mathematical concept some difficult.
T:Students find that mathematical concept somewhat diffi-cult.
F:Mis shirt looks some dirty.
T:His shirt looks somewhat dirty.

44.sit,set.sit不跟宾语;set跟宾语。

F:.The old man is setting on the porch.
T:The old man is sitting on the porch, (present participle)
F:The woman sat the groceries on the table.
T:The woman set the groceries on the table, (past tense)
F:Exhausted, the hiker set down to rest.
T:Exhausted, the hiker sat down to rest, (past tense)
F:Please set here if you're tired.
T:Please sit here if youVe tired, (present tense)

45.so that 指目的,不能省略that。

F:He came here so he could study English.
T:He came here so that he could study English.
F:The spider spins a web so it can catch insects.
T:The spider spins a web so that it can catch insects,

46.such,so.避免用这两个词代替very.

F:Taxes are so high today.
T:Taxes are very high today.
OR
F:Taxes are so high today that some people try to cheat on their tax returns.
F:Professor Davis is such a good lecturer.
T:Professor Davis is a very good lecturer.
OR
Professor Davis is such a good lecturer that students enjoy being in his class.

47.sure和try后面不跟and。

F:You should try and write legibly.
T:You should try to write legibly.
F:I am going to try and get some sleep tonight.
T:I am going to try to get some sleep tonight.
F:Be sure and bring a pencil to class tomorrow.
T:Be sure to bring a pencil to class tomorrow.

48.that名词从句中不能省略that在有一个以上的名词从句是尤应注意。

F:My objection to smoking is it is dangerous to health.
T:My objection to smoking is that it is dangerous to health. F:Everyone knows Greenland is an island and it is located to the north.
T:Everyone knows that Greenland is an island and that it is located to the north.

49.their,there,they're.

F:I am interested in they're habits.
T:I am interested in their habits.
F:Their coming later this afternoon.
T:They're coming later this afternoon.
F:They're coming surprised us.
T:Their coming surprised us.
F:They're several ways to use the word correctly.
T:There are several ways to use the word correctly.

50.too,enough.Too意为to an excessive degree.Enough意为 adequate or sufficient for the purpose desired.

F:Your brother is too old to know better.
T:Your brother is old enough to know better.
F:The window was dirty enough to see through.
T:The window was too dirty to see through.
F:I am too sick to miss class.
T:I am sick enough to miss class.
F:John is too clever to solve the problem.
T:John is clever enough to soive the problem.