They are all working hard ( ) at English.A.on B.with C.at D.in -----------C请赐教,原题中无at

问题描述:

They are all working hard ( ) at English.
A.on B.with C.at D.in -----------C
请赐教,
原题中无at

只有在WORK 后面加ON 和 AT的用法
ON表示某项具体的工作,某个专项计划等等
AT表示大范畴的门类,学科,领域