I want to answer the call of nature.

我想回应大自然的呼唤。

He had to leave suddenly to answer the call of nature.

他不得不忽然离开去处理下内急。

He had to leave suddenly to answer the call of nature.

他不得不突然离开去解决下内急。

Sorry, Sir, I must answer the call of nature-i won't be long.

对不起先生，我得去方便一下，就一会儿。

Does anyone need to answer the call of nature before we set off?

我们准备出发了，有谁想上冼手间？