I see Kate's and Helen‘s skirts are on the sofa.对不对?名词所有格加在哪?

问题描述:

I see Kate's and Helen‘s skirts are on the sofa.对不对?名词所有格加在哪?

我觉得应该是I see Kate's skirt and Helen‘s (skirt ) are on the sofa.
要么I see Kate and Helen‘s skirts are on the sofa.