问题补充:
There is no doubt he will finish the task in time.
A. if
B. whether
C. what
D. that
答案:
A. if
B. whether
C. what
(答案→)D. that
解析:句意,无疑他会按时完成这项任务。there is no doubt 句型中当doubt本身被否定时,其后跟的宾语从句或同位语从句应用that引导;doubt被肯定时,其后的宾语从句用if或whether引导,同位语从句则由whether引导,不能用if引导。故选D.