English riddle

Today, I have no topic so I feel like to give you riddles which are not normal question but playful one. In Japanese we call it 

"nazonazo".

I hope you can make your brain work well.

1.  What kind of pet always stays on the floor?

2. Who is closer to you, your mom or dad?

3.   What letter of the alphabet which has a lot of water?

4.    What five letter word has six left after you take two letters away?

5.   What time is it when the clock strikes thirteen?

I guess they are not so easy but you will learn a kind of sense of humor in English.

The answers are in Japanese version.