[RadioKid]

"DA" has the same meaning as "DESU" and you can use "DA" whenever you can use "DESU" in terms of grammer.

However, "DA" has not the politeness which "DESU" brings. Please be careful to use "DA" when you are talking with people you respect(or people who expect you will take respect to him).

I hardly use "DA" in main sentense in talking. As "DA" is too strong and forces opinion to the listener, I often use "DAYO" or "DANE" instead of "DA" to soften it.

RK