467.Mother wanted to be a good provider,a role she ______ since her marriage to Father.
A.shoulders
B.shouldered
C.is shouldering
D.has been shouldering
468.I have to see the doctor because I _______ a lot lately.
A.have been coughing
B.had coughed
C.coughed
D.cough
467.答案是D;含有since引导的状语从句通常与完成时连用，而用现在完成进行时则表示动作还将继续下去。
468.答案是A;由lately得知现阶段一直在咳嗽，故用现在完成进行时。
