3、bikeoverthere?Ihavehaditforthreeyears?IhavehaditsinceIwasachild.Askstudents;Doyouknowthedifferencesbetweenthem?since:(自…以来)1)since+时间点He has stayed here since 5 o’clock.2)since+时间段+agoHe has stayed here since 5 hours ago.3)since+从句She has taught English since he came here.for:(长达)for+时间段Hehask