There might be life on other planets but so far scientists haven’t found enough to prove

问题补充：

There might be life on other planets, but so far scientists haven’t found enough to prove it.

A. evidence

B. relic

C. mystery

D. reception

答案：

(答案→)A. evidence

B. relic

C. mystery

D. reception

解析：句意：在其他星球可能有生命，但是到目前为止科学家没有找到足够的证据证明。Evidence证据；relic遗迹；mystery秘密；reception接待，选A。