28、According to statistics,a man is ________ to die of skin

28、According to statistics,a man is ________ to die of skin cancer as a woman.
A.more than twice as likely B.twice more than as likely
C.as likely more than twice D.twice more than likely as
正确答案是A ,为什么不选B
29、Everyone knows that _____ is dangerous to play with fire,but _____ is difficult is to prevent children from playing with fire.
A.it,it B.what,what C.it,what D.what,it
正确答案是C ,为什么不选A
30、With more forests being destroyed,huge quantities of good earth _____ each year.
A.is washing away B.is being washed away
C.was washing away D.are being washed away
正确答案是D ,为什么不选B