Answer:
I help you carry your books.
I can point in every direction but can't reach the destination by myself. What am I?
I fly when I'm on and float coming off.
I have married many woman but has never been married
I am always in front of you, but you will never see me. What am I?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.