当艾伦意识到这一点，他就知道了希尔伯特的问题的答案。

And once he had seen this, he knew the answer to Hilbert's question.

youdao

当艾伦意识到这一点，他就知道了希尔伯特的问题的答案。

And once he had seen this, he knew the answer to Hilbert's question.

youdao