—You may find the key to the math problem on page 107．
—Ah, it's so simple. I wonder why I of that．
A. hadn’t thought
B. haven't thought
C. didn't think
D. wasn't thinking
网友回答
A. hadn’t thought
B. haven't thought
(答案→)C. didn't think
D. wasn't thinking
解析：考查时态。句意：—你在107页上可以找到这个数学题的答案。—啊！太简单了！我想知道为什么我就想不起来这个答案呢?根据句意说明我没有想起这个答案是过去的事情，故使用一般过去时。故C正确。