SINCE 1980, SCIENTISTS THE WORLD OVER _____ A LOT OF THINGS TO...

Question

Câu 27. Since 1980, scientists the world over _____ a lot of things to fight against AIDS.   A. are doing  B. had done  C. did  D. have done

Accepted Answer

1 [] C 2 [] C 3 [] C 4 [] A 5 [] C 6 [] C 7 [] B 8 [] D 9 [] C 10 [] A 11 [] A 12 [] A 13 [] A 14 [] A 15 [] D 16 [] C 17 [] C 18 [] C 19 [] C...