Question

What would have happened＿＿＿＿, as far as the river bank?

A．if Bob has walked farther	B．if Bob should walk farther
C．had Bob walked farther	D．if Bob walked farther

Answer 1

C

此题表示与过去事实相反的假设，主句用would have done,从句用had done,此处用了倒装的省略形式,即省去if, had提到句首。