Answer:
What can you catch but not throw?
As I went over London Bridge I met my sister Jenny; I broke her neck and drank her blood and left her standing empty.
My voice is tender, my waist is slender and I'm often invited to play. Yet wherever I go, I must take my bow or else I have nothing to say. What am I?
What is made of wood, but can't be sawed?
Everyone asks for me but yet everyone hates to face me. For someone I am agony for others I am relief. Who am I?
No matter how little or how much you use me, you change me every month.