Theelderly______goodcareofinpublicplaceslikesupermarketsandairports;theyarelikelytogetlost.
A.can have been takenB.ought to be takingC.must be takenD.should take在线课程C
词义辨析。主语The elderly和take good care of是动宾关系，要用被动形式，排除B,D；can have been taken，可能已经被照顾；must be taken必须被照顾。句意：老人在公共场所，例如超市和机场，必须被好好照顾；他们很可能会迷路。所以选C。