since = desde
Mary has changed a lot since she and Peter split up.
Mary ha cambiado bastante desde que ella y Peter se separaron.
George and Ron are much happier since they live together.
George y Ron son mucho más felices desde que viven juntos.
Since she started working in this new company, she has earned a lot of money.
Desde que comenzó a trabajar en en esta nueve empresa ha ganado mucho dinero.