Correct or Improve the translation of the following English sent

Correct or Improve the translation of the following English sentences.原文：Obama also called climate change and nuclear proliferation “challenges that neither of our nations can solve by acting alone." 译文：奥巴马也把气候变化和核扩散称为“我们两国都无法单方面解决的挑战” 。
【正确答案】：

奥巴马也把气候变化和核扩散称为“我们两国都无法单方面应对的挑战”。

【题目解析】：奥巴马也把气候变化和核扩散称为“我们两国都无法单方面应对的挑战”。(考点：动宾搭配：solve challenges)