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As its sales of computer products have surpassed
those of measuring instruments, the company has
become increasingly willing to compete for the mass
market sales they would in the past have conceded to
rivals.
?? (A) they would in the past have conceded to rivals
?? (B) they would have conceded previously to their rivals
?? (C) that in the past would have been conceded
previously to rivals
?? (D) it previously would have conceded to rivals in the
past
?? (E) it would in the past have conceded to rivals  

答案是E


但是为什么要用虚拟语气呢？
为什么不说 it in the past conceded to rivals。。。