Unlickily there many thousands of children w____ can not go to school.
问题描述：
Unlickily there many thousands of children w____ can not go to school.
答
Unlickily there （are） many thousands of children （who） can not go to school.
很不幸,有许许多多上不起学的孩子.
这里应该是填定语从句的引导词who,指代先行词children.