Work hard at my study还是on my study?

work hard at hard Work hard at my study还是on my study? I work hard at school.So ____(do)my brother I work hard at all my subjects是什么意思? 英译汉:work hard at work hard at中文 work hard in还是work hard at? 有没有work hard to my job 这种说法的?或者说应该是work hard at my job? work hard at English是什么意思 I work hard at school. hard at work school I(? At work,I must work hard 是work hard at sth.还是work hard on sth. work hard at和work hard on 的区别 It's my duty to work hard at school.同意句____ ______ at school_____ _______ my duty. I have to work hard at my lessons from now on.翻译下```at my lessons什么意思 now on work hard with/at/in/on my English以上4个哪个对,WHY He wishes me ______(do) my best _____ (work) hard at English.