Friendship phrases:
1. Get in touch (with someone): start contact again after not speaking for some time
2. Keep in touch (with someone): continue contact
3. Get on (with someone): have a good relationship
4. Go out (with someone): have a romantic relationship
5. Lose touch (with someone): have no more contact
6. Catch up (with someone): find out what has happened during the time you haven't spoken to someone
7. Fall out (with someone): stop being friends after an argument