When he was alive, the old scientist use
题型：选择题
问题：
When he was alive, the old scientist used to say that knowledge ＿＿＿＿from practice and he gained his experience by doing a lot of practical work.
A．was coming
B．had come
C．comes
D．would come
When he was alive, the old scientist used to say that knowledge ＿＿＿＿from practice and he gained his experience by doing a lot of practical work.
A．was coming
B．had come
C．comes
D．would come