Then over dinner,Franklin mentions that he well since he gave up smoking and Dr Candy,the local doctor,offers to write him a prescription for some medicine.A.had not been sleepingB.has not been sleepingC.is not sleepingD.was not sleeping
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B解析根据语法since是“自从……以来”，前面一般用现在完成时，表示一直睡不好，应用现在完成时的进行时。