2,Tom is____brother.A,Lucy and Lily's B,Lucy's and Lily C,Lucy's and Lily's D,Lucy and Lily.请解释

问题描述:

2,Tom is____brother.A,Lucy and Lily's B,Lucy's and Lily C,Lucy's and Lily's D,Lucy and Lily.请解释

选a 后一个人名加`s 前一个不加