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 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：名词词义辨析。A证据；B遗址，遗迹；C秘密，谜；D接待，欢迎；句意：在其它的星球上也许又生命，但是到目前为止科学家们还没有找到足够的证据来证明这一点。故A正确。