(your) mind is on (something)

have (your) mind on (something) - to be thinking about something.

I wasn't really listening - my mind was on other matters.

• the red-light district
• Therein hangs a tale.
• There is more to someone than meets the eye.
• There is more to something than meets the eye.
• there is never a dull moment
• there is no such thing
• there isn't a [mean, jealous, unkind etc.] bone in body
• there isn't a [mean, jealous, unkind etc.] bone in someone's body
• there is safety in numbers
• there'll be hell to pay
• there's a lot to be said for
• there's a lot to be said for doing something
• there's a lot to be said for something
• There's a time and a place.
• There's life in the old dog yet.
• There's many a slip twixt cup and lip.
• There's many a true word spoken in jest.
• there's method in madness
• there's method in someone's madness
• There's more than one way to skin a cat.
• there's much to be said for
• there's much to be said for doing something
• there's much to be said for something
• There's no accounting for taste!
• there's no law against