Only in 1996 the determination and patience of the scientists with a breakthrough at last .
A.were ; paid off | B.did; pay back | C.did ; pay off | D.did ; pay for |
推荐套卷
Only in 1996 the determination and patience of the scientists with a breakthrough at last .
A.were ; paid off | B.did; pay back | C.did ; pay off | D.did ; pay for |