In reply to "a full moon and the sun cannot be seen in the same part of the sky simultaneously" . . .
It can...
For an observer in England, what is the date and time of the next occasion when such an observation can be made? What was the time, date and location for some previous occasion within the last 32 years when such an observation was made?
I asked how you know what shape the moon has, and you replied "It's flat like the earth"... that doesn't answer my question. I wasn't asking you to state the moon's shape, I was asking how you know the moon's shape.