1. Look before you leap. - He who hesitates is lost (or You snooze, you lose
)
2. Out of sight, out of mind. - Absence (or absinthe) makes the heart grow fonder
7. Opposites attract. - Like attracts like
9. Many hands make light work. - Too many cooks spoil the broth
12. Beware of Greeks bearing gifts. - Don't look a gift horse in the mouth