A Twist of Language

A handful of riddles for you. 

*What comes once in a minute,

Twice in a moment,

But never in a thousand years?

*By night they come without being fetched,

By day they are lost without being stolen.

*Light as a feather with nothing in it,

A strong man can’t hold it

Much more than a minute.

*What has a bottom 
at the top?

*What has six legs,

Two heads,

One tail and four eyes?

                             XO,

                             April

(letter M, stars, a breath, a leg :), a person on horseback)