问题补充:
It long before we the result of the experiment.
A. will not be;will know
B. is;will know
C. will not be;know
D. is; know
答案:
A. will not be;will know
B. is;will know
(答案→)C. will not be;know
D. is; know
解析:考查固定句型。It be 一段时间 before从句。意为:一段时间以后某事才发生。Before从句里用一般现在时代替将来时,主句用将来时。故C正确。