ash
[the part left after something burns]
Only ashes were left when the fire passed.
ask
[(1) to question; (2) to say something is wanted] We ask the teacher questions every day. (1)
The candidate asked the people for their votes. (2)
assist
[to help]
The doctor asked the medical student to assist him.
astronaut
[a person who travels in space]
Astronaut Neil Armstrong was the first man to walk on the moon.
astronomy
[the scientific study of stars and the universe] I study astronomy because I like to look at stars.