use a comma after introducttry elements in a sentence...can you give me an example if that kind of sentence??

I'll give you more than one:

Introductory adverbial clause --
When we finished eating dinner, my brother and I cleared the table and did the dishes.

Introductory phrase --
On June 26, 2000, my college roommate got married.

http://grammar.ccc.commnet.edu/grammar/commas.htm
See #3.

=)

thanks

George, will you please turn down the TV.

After you've mowed the lawn, you can play a computer game.

Check this site for more examples.

http://web.uvic.ca/akeller/wherecomma/introductory_elements.html

Certainly! When using introductory elements in a sentence, it can be appropriate to use a comma after them. Here's an example sentence where a comma is used after an introductory element:

- "After finishing his work, John went for a walk in the park."

In this sentence, "After finishing his work" is the introductory element. By using a comma after the introductory element, it helps to separate it from the main part of the sentence.