TO + VERB AFTER IT'S...
Eating in public is bad manners.
Not shaking hands is impolite.
It's impolite not to shake hands.
It's bad manners to eat in public.
People might stare at you for not shaking hands.
VERB + -ING AFTER PREPOSITIONS
VERB + -ING AS A SUBJECT
You can offend people by eating in public.
