21.______ convincing an argument is,it needs support of evid

21.______ convincing an argument is,it needs support of evidence.
A.Whatever
B.However
C.Although
D.Even if
满分：2.5 分
22.“Paul was riding a bicycle along the motorway when he was hit by the trailer of a lorry.”“He _____ a bicycle along the motorway; bicycles are not allowed.”
A.shouldn’t have been riding
B.couldn’t have been riding
C.oughtn’t have been riding
D.can’t have been riding
满分：2.5 分
23.“Tell the students to stop shouting.We ______ our essays now.”
A.write
B.have been writing
C.are writing
D.have written
满分：2.5 分
24.Had electronic computers not been invented,many problems of space flight ______.
A.could be not solved
B.could not be solved
C.could not have been solved
D.could not have solved
满分：2.5 分
25.No sooner had he finished his speech ______ stormy applause broke out.
A.when
B.then
C.than
D.as
满分：2.5 分
26.I‘m sure dirty,______?
A.am I
B.isn’t I
C.aren’t I
D.am not I
满分：2.5 分
27.Tuition at American university runs ______ one thousand dollars a semester.
A.so high as
B.as high to
C.as high as
D.as higher than
满分：2.5 分
28.I wish to recollect where I met her,______?
A.would I
B.may I
C.may not I
D.can I
满分：2.5 分
29.______ think he will ______ dare the risk.
A.not/ ..
B.do/not
C.../not
D.don’t/..
满分：2.5 分
30.The little boy dare not go to church,______?
A.dare he
B.daren’t he
C.does he
D.doesn’t he
满分：2.5 分