Question

I could hardly believe that he would be stupid enough to do that,______

是could I 还是would I?
答案是would he 刚才打错了

Answer 1

I could hardly believe that he would be stupid enough to do that,__would he?
应该是 would he？
我简直不能相信他会这么笨做那件事。

这道题主要是考察反问句的提法，你需要先找到句子要突出的的主干事实部分应该是：he would be stupid enough to do that
所以反问时应该对这部分进行提问，而不是前面的I could hardly believe
所以是would he？而不是 could I？
又因为hardly使得整个句子有了否定语气，反问时则需用肯定式反问would he而不用wouldn`t he?

Answer 2

首先是否定
其次看主句
否定前移
是would he

Answer 3

...看句首，反问就用句首 COULD I