it's a wast of time 为什么有a 去掉a可以吗?

it's a wast of time 为什么有a 去掉a可以吗? a wast of time!是 It's an important decision for you,so____ your time and drink it over.A.take B.wast C.cost It's a waste of time exactly! It's better to spend more time on your schoolwork than ___ time on computer games. A waste B to wastA waste B to wast C wasting D wasted 答案是C 但我觉得应该是B　请指教 It's time of wast bookstore it is of the连词成句 It's all a matter of time的意思 Mary always s()a lot of time reading in it . Youth is not a time of life,It's a time of your imagination It's a waste of time改为感叹句并说明理由______ _________wastw of time It's the Spring Festival,and it's a very b______l time of Chinese.怎么写! it‘s that ------time year again.A.for B.of C.for a D.of a It 's the same time ( ) year.A.for B.of C.for a D.of a wast 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? A motorboat,which has a speed of 5 meters per second in still water,is headed wast as it crossesa river flowing south at 3.3 meters per second.What is the magnitude of the boat's resultant velocity with respect to the starting point?有点晕,为什 翻译：It's a waste of time and I wish I had never seen it