He with his friends usually_(play) football after school.

问题描述:

He with his friends usually_(play) football after school.

plays
一个句子的主语被with/together with/as well as等短语+n.修饰时 句子谓语的数根据前面的名词确定
这个句子就是he被with his friends修饰 所以play的数由he确定