Answer:
Lovely and round, I shine with pale light. Grown in the darkness, a lady's delight. What am I?
As I went over London Bridge I met my sister Jenny; I broke her neck and drank her blood and left her standing empty.
When it comes to me, you go on red and stops on green. What am I?
David's father has three sons: Snap Crackle and ?
I turn everything around but I cannot move. When you see me you see you!
No matter how little or how much you use me, you change me every month.