Scientists have made a major __ in cancer research.

Scientists have made a major __ in cancer research. Chinese scientists have made a great__in genetics in the pas 改错Scientists have already made a sheep scientists have made a lot of important d___ in science in t 一道单选题Scientists have made a great ______ in the treatment of they __ to have discovered a cure for cancer. 一道介词选择2 ___ research ___ the universe scientists have put a ___ research ___ the universe scientists have put a lot of i ____ scientists have done a lot of research on A1H1N1 flu,th I hope scientists _____（find)a cure for cancer Cigarette smoking is a major factor contributing to cancer. Cigarette smoking is a major factor____to cancer.