What pronoun should I use if there's two different gender?

1. when students come to class, everyone.

2. ricardo hasn't seen his father in six months. when you see it,.

3. good friends when they're in trouble.  

4. it's the end of the wedding. the groom and the bride.

5. my girlfriend and i are getting married because a lot.

6. irene and vicente many electronic messages when you don't see them.

7. i talk to my sister every day. we do every day.

8. when sandra goes out to eat with her friends, they at the restaurant.

explanation:

as i can translate spanish i'm thinking that you want the translation so here they are for each one of them.

hopes this you mi amigo : ).