FOUR RHYMING RIDDLES

1)
Once in 10,
Twice in 20,
Thrice in vice.

2)
Walk on water with its power,
Try to keep it, it's gone in an hour.

3)
We are five little objects of an everyday sort;
You will find us all in a tennis court.

4)
I stare at you. You stare at me.
I have three eyes, but cannot see.
But I can blink, and do all day,
And when I do, you'll do just as I say.

Answers:

1. X
2. Ice
3. Vowels
4. Traffic light