It's a waste of time,这个a是表示什么?这个a表示什么?语法上怎么解释?

It's a waste of time exactly! It's _____to play computer games.(A:waste time B:a wsate of time C:waste of time D:a waste time)选哪个?为什么? It's a waste of time改为感叹句并说明理由______ _________wastw of time It is only a waste of time it was a waste of time and 翻译：It's a waste of time and I wish I had never seen it a waste of time It's a waste of time .What you have done is____(use) It`s a waste of time.（改为感叹句）求解答? It's really a waste of time.（改为反意疑问句的形式） I think it's waste of time to hang it's a waste of time to spend so much time on computer games is isn't_____ ______so much. 请问:It's a waste of time.是浪费时间,那么a waste of waters为什么又译成茫茫大海 一片汪洋 is,talking with,of,her,waste,time ,a,it, It's a waste of time,这个a是表示什么?这个a表示什么?语法上怎么解释? 请问:It's a waste of time.里面为什么有个a是浪费一个时间吗 It's a waste of time这个句型,急,It's a waste of time 后面加to do sth还是doing sth?到底哪个正确呢?还是两个都有? 是It is a waste of time to play computer games 还是Playing computer games is a waste of time