work hard on , work hard at, work hard for 和work hard to的用法之差异

work hard in 还是work hard on 是work hard at sth.还是work hard on sth. work hard on和work hard atRT 区别?联系? work hard at和work hard on 的区别 work hard on , work hard at, work hard for 和work hard to的用法之差异 work work hard Work hard work hard this is ____ ,so we must ____ on it.A.a hard work;hard work B.hard work;work hardC.hard work;hard work D.a hard work;work hard work hard on the Pyramid怎么解释 work hard at hard play hard-work hard work hard?work smart?翻译 All the chilldren work hard at还是work hard on our lessons work on与work work hard in还是work hard at? “work hard”和“hard work”的区别. hard work,work hard 有什么区别?