[例9]No one doubts______it is true.
A.whether　B.if　C.that　D.what
【解析】答案C。doubt用在肯定句中后接if引导的从句，用在否定句中后接that引导的从句。
[例10]There is much chance______Bill will recover from his injury in time for the race.
A.that　B.which　C.until　D.if
【解析】答案A。that在此引导同位语从句，修饰chance，又如：There was a chance that my letter would arrive in time.我的信有可能准时到达。
[例11]We haven’t settled the question of______it is necessary for him to study abroad.