问题
I won’t tell the student the answer to the math problem until he ________ on it for more than an hour
A:has been working
B:will have worked
C:will have been working
D:had worked
B:will have worked
C:will have been working
D:had worked
正确答案是：
同类题型
Surely Mr. Peterson ____ have forgotten to buy presents for his beloved family members.
No one knows ______ the task will last. What a pity!
Just a moment . I haven’t finished packing my suitcase.—- .Itshigh time we left for the airport.
Which of the underlined(划线) part has a different pronunciation(发音)