he has not come back home

问题描述:

he has not come back home
his mother (is worrying )about him ,括号里的能换成is worried

he has not come back home 完成时态,表示他没回来这个结果.his mother (is worrying )about him正在进行时,表示正担心着他 ,符合上文的语境.is worried 表示一种担心的状态,没有用进行时更形象.