问题
选择题
This is _____ and we must _____ on it.
A hard work; work hard B a hard work; work hard
C hard work; hard work D work hard; hard work
答案
答案：A
题目分析：句意：这是艰苦的工作，我们必须努力工作。Hard work艰苦的工作；work hard努力工作。英语中work为不可数名词，故选A。