一到英语选择题

They wouldn't be feeling so tired if they 横线 for a whole day.

A,weren't walking

B,didn't walk

C,hadn't been walking

D,hasn't been walking

简单解释一下，谢谢

选C。是虚拟语气。属于下面的第三种。

用if条件从句表示的虚拟条件

　　① 虚拟现在时表示与现在事实相反的假设，其if 从句的谓语形式用动词的过去式(be 一般用were)，主句用would/ should/ could/ might +动词原形，例如：If I were in your position I would marry her.

　　② 虚拟过去时是表示与过去事实相反的假设，if 从句的谓语形式用过去完成时即had＋过去分词，主句用would / should / could / might + have +过去分词，例如：If it had not rained so hard yesterday we could have played tennis.

　　③ 大多数的虚拟条件句属于上面三种情况的一种，但并不排除存在条件和后果中，一个和现在情况相反，另一个和过去情况相反，例如：If you had followed what the doctor said, you would not have been so painful now.这个句子在高中出现频率颇高

C.解释如下:如果他们没赶一天的路,就不会这么累了.

A为过去进行时,显然不符;B为一般过去式,也与前文中would不符;D就不用说了,单数肯定不行.

C为过去完成时,正确答案!