Does he have a ( ) brothers or sister

问题描述:

Does he have a ( ) brothers or sister

填twin
首先由于有了 一个“a”,所以直接排除any,绝对不会有have a any ...这种表达方式的
然后看borhter【S】与sister【S】,只有填twin brothers与twin sisters的时候,brothers 与sisters才需要特别加上S,所以应该是填twin