work hard on

work hard on work hard on和work hard at 是work hard at sth.还是work hard on sth. work hard at和work hard on 的区别 Work hard so as to finishing the work on time. work hard on the subject,work hard at English,in your lesson All the chilldren work hard at还是work hard on our lessons this is ____ ,so we must ____ on it.A.a hard work;hard work work hard play hard-work hard work hard at hard Our s______ depends on our hard work,perseverance and determ