Therapists cannot read clients' minds. That is a psychic ability, yes?
Psychologists and therapists can hear clients out and get an understanding of their experiences, through mutual dialog.
I wonder though, why you think that it would be helpful if therapists could do so? As a client, would you wish that therapists could read your mind? Even then, I doubt if you would be okay with someone just knowing everything that's running in your mind in a moment, that might be just scary, yes? I believe you might want some control over what others could know about your thoughts and feelings - things you'd not like them to know and things you would really like them to hear. Yea? I would invite you to reflect then.... if there are any such things you would wish for the other to know, but are somehow unable to share? In such a case, it might help to identify what the barriers are, for you, in sharing about those things... what kind of fears or concerns might be holding you back from being able to let the other person know about something you really want them to hear.
Hope this answers your question to a satisfactory extent.