It was not until then that I came to know knowledge ________ onl

It was not until then that I came to know knowledge ________ only from practice.
A、had come
B、has come
C、came
D、comes
【正确答案】：D
【题目解析】：客观真理始终用一般现在时来表示，句中knowledge是不可数名词，因此选D项。