英语.Manyexpertshaveraiseddoubtsaboutitisrighttojudgeteachers'Manyexpertshaveraiseddoubtsaboutitisrighttojudgeteachers'performanceonstudents"testscores.A.thatB.whatC.whetherD.ifIdon'tdoub

Question

英语.Many experts have raised doubts about ____ it is right to judge teachers'
Many experts have raised doubts about ____ it is right to judge teachers' performance on students" test scores.
A.that   B.what   C.whether   D.if
I don't doubt____ he'll come.
A.if   B.whether    C.that   D.what                       
第二题为什么选C，不选B.请说明理由，

Answer 1

B.whether " 是否",引导宾语从句,在介词后不能用if .
C.that
因为I don't doubt后是一个宾语从句,宾从中的come是不及物动词,不能带宾语.所以不能选D.因为what在宾从中必须充当成份.而that在宾从中不充当成份,所以选C.