I've just come across that phrase
I don't know if you can tell or not, but...
Would you tell me what it means and how I can use it?
Thanks for your help
I am not sure if you notice something
I don't know if you can tell or not, Rose has been pretty upset recently.
it means that I think Rose has been pretty upset and I am curious if you have noticed the same thing about her.
Also pretty good explanation here