单选题Thatwasareallyverydifficultquestio

问题补充：

单选题That was a really very difficult question. But a little child ________ a good answer. A.came up toB.came up withC.caught up withD.came upon

答案：

B解析那个问题确实很难，但是一个小男孩给出了一个很好的