Meaning : Be unable to remember.
Example :
I'm drawing a blank.
You are blocking the name of your first wife!.
Synonyms : blank out, block, draw a blank
Meaning : Forget to do something.
Example :
Don't forget to call the chairman of the board to the meeting!.
Meaning : Leave behind unintentionally.
Example :
I forgot my umbrella in the restaurant.
I left my keys inside the car and locked the doors.
Synonyms : leave