英语翻译:“used to say which subject or activity.”

问题描述:

英语翻译:“used to say which subject or activity.”
“used to say which subject or activity you are talking about when you say whether someone is skilful ,successful etc or not”
这是字典里关于 at 的解释 ,就这些了,帮忙翻译一下吧

过去常说哪个主题或活动你在谈论 当你说某人是否娴熟、成功与否.