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
Pierre Curie ______ his own research workand joined Madam Curie in the search for radium.
We could make it from here to Florida if we drove all night.—— ___________! It’s a three-day drive.
label _______ to each luggage, itwon’t take you long to find yours
I want to buy a car for my father, buthaven’t found he likesyet.