----Jack, is maths difficult to learn in High school?
----Sure. No subject can be learned well hard work.
A. without
B. through
C. by
D. with
网友回答
(答案→)A. without
B. through
C. by
D. with
解析：考查介词的用法。根据对话情景，答语中的意思是：肯定了数学在高中难学，而且补充说明哪门课程都需要刻苦学习才能学好。因为本句是个否定句，所以要用表示否定的介词without。