Is this a bee or a fly?  ?

i don't know what that is

It's a drone fly (also called a hover fly), Eristalis tenax. The wing venation makes possible a definite identification.

The eyes are too big to be a bee,,it is a fly, one of the lookalike sort such as hoverfly.

Totally harmless, they don't sting or bite.

L. N.  is right, so I'll just add this:

.

A fly and a flea in a flue

Were trapped, so what could they do?

Said the fly, "let us flee."

Said the flea, "let us fly."

So they fled though a flaw in the flue.

Flies have one pair of wings, bees have two pairs of wings. I only see one pair in your photo so it must be a fly.