You ought to have put the milk in the refrigerator;now( )sour

题目

You ought to have put the milk in the refrigerator;now( )sour
A.I smell B.it is smelt C.it smells D.it is smelling
该题正确答案应选C,说明其他几项为什么不对,

答案

smell 感官动词不用被动,不能用进行时