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
出自:中北大学-大学英语1

完成拼图验证

按住下方滑块,将拼图拖到缺口处后松开。

拼图背景,将小拼图拖到缺口处
向右拖动滑块