It was not until then that I came to know that knowledge only from practice.A. had comeB

问题补充：

It was not until then that I came to know that knowledge only from practice.

A. had come

B. has come

C. came

D. comes

答案：

A. had come

B. has come

C. came

(答案→)D. comes

解析：考查时态。本句中的knowledge comes only from practice是一个客观真理；在任何情况下都使用一般现在时。故D正确。