mind you
We use this expression to introduce an idea or fact that contrasts with the previous idea in some way.
我们用这个表达来引入一个想法或事实，在某种程度上与之前的想法形成对比。
A：It took my friend 10 hours to finish the London marathon. Mind you, she is over 80.
我的朋友花了10个小时才跑完伦敦马拉松。注意，她已经80多岁了.
B：Well then, it's amazing that she finished it at all.
那她能完成就真的很不可思议了。