My uncle ______ until he was forty-five.(上海2000)

题目

My uncle ______ until he was forty-five.(上海2000)
A.married B.didn’t marry
C.was not marrying D.would marry
b答案和c答案的区别在哪里,它们都是过去式的否定形式,为什么不选c?

答案

C. was not marrying使过去进行式,所以不对.