几道英语选择 Were filming by the lake----we saw a small boat comin

几道英语选择 Were filming by the lake____we saw a small boat coming towards usa since b after c when d beforeMum ,l can't bear the pain lt won't be long ___the doctor comes a while b before c since d asEveryone should remain ___until the film finishesa seat b seating c to seat d seatedHe doesn't smoke now ,but he was a heavy smoker __he had a lung cancera as b since c until d after