it's (),so we must().A a hard work,work hard B work hard,hard work C hard work,work hard
问题描述：
it's (),so we must().A a hard work,work hard B work hard,hard work C hard work,work hard
答
C it is hard work,so we must work hard.
第一个hard意思是困难的,是个形容词,work做工作讲,不可数,所以前面不能加a.
第二个work是动词,hard是副词,努力地.
翻译为：工作很困难,我们必须努力.