题目内容
---European scientists announced that the speed of light isn’t the speed limit.
---Perhaps it is the biggest challenge to Einstein’s Theory of Relativity.
No one _____ any crack in his
theory for more than a century.
---Perhaps it is the biggest challenge to Einstein’s Theory of Relativity.
No one _____ any crack in histheory for more than a century.
[ ]
A. has found
B. found
C. had found
D. would find
B. found
C. had found
D. would find
C
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