Mis amigos a las fiestas todos los días.

Here we must complete the sentence:

"mis amigos a las fiestas todos los días."

That means something like:

"My friends to the parties all days"

Where the word that completes the blank would be something like "go" or "go out"

There are some ways to complete the sentence, the most formal one would be:

"mis amigos salen a las fiestas todos los días."

Or

"mis amigos van a las fiestas todos los días."