beet - bēt
beat - bēt
bit - bit
The first 2 are identical and should be pronounced with a long "E" sound. like the word "Bee" followed by a "t" sound.
Bit is a little "b" sound like in "base" so it "b" followed by an "i" sound like in "hit" followed by a "t"
I hope this helped, it is hard to explain in writing.
Best of Luck,
Jack Lindsay