[Mr/ Mahmoud.K]

Was - were - is - are - am ) + used to + V.ing
إذا سبق used to اي من مشتقات verb to be لابد أن ياتي بعدها V + ing
وهذه حالة شاذة للفعل مضاف له ing بعد to
وكذلك in addition to / look forward to يأتي بعدها V.ing أو noun