解释keep to 和a waste of time 和be short of 并分别造句
问题描述：
解释keep to 和a waste of time 和be short of 并分别造句
答
keep to 保持.He kee to study hard.
和a waste of time 浪费时间.It is a waste of time to argue with him.
和be short of 短缺.We are short of food.