Answer---stars or dream either will do.

No 3---My life can be measured in hours;
I serve by being devoured.
Thin, I am quick; fat, I am slow.
Wind is my foe.
What am I? 

Answer--- A Candle

No 4---To unravel me
You need a key.
No key that was made by locksmith's hand,
But a key that only I will understand.
What am I?

Answer---Cipher

No 5---How many grooves are there on an LP record?

Answer---Just two one each side.

No 6---Whoever makes it, tells it not. Whoever takes it, knows it not. Whoever knows it, wants it not. What is it?

Anwer---

Counterfeit money.

No 7---My tines be long,
My tines be short
My tines end ere
My first report.
What am I?

Answer---Lightning