C six months' 用’s 属格
或者合成形容词 six-month 【数词-名词单数】,B 错在有个a,training 不可数
请在客户端右上角评价点“满意”即可holiday training说几天几个月的时候是two days'hoilday/training【还有哪些词是这么使】【一个几岁的孩子是a six-year-old child还有哪些词是这么使？】two-day hoilday/training a six-year-old child=a child aged six= a child who is six= a child who is six years old= a child at the age of six= a child who is xix years of age