“为什么”造句

不知为什么他讲这些故事时一点都不害怕。
Somehow he tells these stories without a note of horror.

我真的不明白为什么要改变它。
I really don't see any reason for changing it.

你真自以为是。我们为什么要费那么大的力气？
You flatter yourself. Why would we go to such ludicrous lengths?