nub
n[sing]
the ~ of sth central or essential point of a problem, matter, etc (问题、 事情等的)中心,要点
The nub of the problem is our poor export performance. 问题的关键是我们出口贸易方面太差.
🗣️ 情景例句
I hear you're expecting a baby, Mrs. Stewart.
我听说你们快有小孩了, Stewart太太。
I don't think so. I know several convenient hotels. Let me make some calls.