题干
— How much did he charge you ___ the service?
— Luckily, it's free ___ charge.
A：for ; of
B：for ; for
C：of ; for
D：of ; of
答案(点此获取答案解析）
A
— How much did he charge you ___ the service?
— Luckily, it's free ___ charge.
A：for ; of
B：for ; for
C：of ; for
D：of ; of
双只有颜色不同的手套中随机的取出
只，则恰好有两只成一双的概率为（ ）