the answer is B,tell me why.thanks

问题描述:

the answer is B,tell me why.thanks
-did jack take the doctor's advice that he____in bed for a couple of days.
-if only he_______.
A lies ; does B lie ; had C must lied ; would D lay ; did

两个空都是练习的虚拟语气.
advice的同位语从句 ,( should ) do
if only 要是.就好了.用过去式.