As and While and Simultaneous expressions.

[Nanatuha]

Dear teachers.
What is difference between these simultaneous expressions?
(I guess someone might ask similar question before but the keyword is so common that I wasn't able to found out.)
1.The earl had a meal as playing cards.
2.The earl had a meal while playing cards.
3.The earl had a meal playing cards.
And the tense used in front and after is not corresponding in my sentence. Should I make them same tense?
Thanks in advance.

[Casiopea]

"while" means, at the same time as:

2) The earl had a meal while playing cards.

[Nanatuha]

Thank you, Casiopea. And I discovered a profitable reference, too. It explained enough about what I wanted to know.
http://www.bbc.co.uk/worldservice/le...rnitv294.shtml
But I got another problem... I'm afraid it's somewhat foolish question, though...
I couldn't clearly get what your answer meant. Did you mean "while" is most preferable?

[Casiopea]

That's correct, Nanatuha. Sentences 1. and 3. are ungrammatical (*). Sentences 2., with "while", is grammatical.

1. *The earl had a meal as playing cards.
2. The earl had a meal while playing cards.
3. *The earl had a meal playing cards.

All the best.

[Nanatuha]

Thank you much.

[Casiopea]

You're welcome.