reciprocal, empirical, emphatic, theoretical辨析

Until people could conduct experiments from outer space, there was no ______proof of Einsteins Theory of Relativity, E=MC2.

A. reciprocal B. empirical C. emphatic D. theoretical

选择什么正确选项呢？如何理解句子意思呢

Until people could conduct experiments from outer space, there was no empirical proof of Einsteins Theory of Relativity, E=MC2.

参考疑问：在大家能在太空进行实验之前，爱迪生的相对论的实验证据还没出现，E=MC2.

A. reciprocal 互相的；相应的；互惠的

B. empirical 经验主义的;以经验为依据的,以察看或实验为依据的

C. emphatic 强调的;着重的;加大语气的

D. theoretical理论的，理论性的,理论上的;推想的