Önceki kadar genç olmadığını unutma.
 - Keep in mind that you're not so young as you used to be.
Onun senden daha genç olduğunu unutmamalısın.
 - You must keep in mind that she's much younger than you.
Bear in mind that I'm not as young as I was, so don't walk so fast.
Keep in mind that he does not hear too well anymore, so you may have to speak more loudly.