use of before, ago, earlier, back

[sona_mylife]

could u plz tell me the correct usage of before ,ago, earlier and back.

[Saxonlight]

How about some examples?

Before:
"I have never seen that car before."
"Before you go out, comb your hair."
"To go where no man has gone before."

Ago:
"Many years ago dragons roamed the land."
"I saw her leave about 30 minutes ago."
"That happened many moons ago."

Earlier:
"Earlier today the temperature reached 100F."
"Bill arrived at work earlier on friday as traffic was light."

Back:
"Back before the guns were invented, swords were a very popular weapon."
"Go back to the start of the race."
"It is impossible to back in time."
"Parking can be found back behind the store."

Hope this helps a bit.

Chris
http://www.hearseesay.com