主语从句?还是什么?what was less visible then,however,were the new,po

主语从句?还是什么?what was less visible then,however,were the new,positive forces that work against the digital divide.”what was less visible then”在句子中做主语从句对吗?”what”引导主语从句的时候后面可以不用n／pron吗?后面”that”引导的是定语从句?有work against这个短语吗?what引导主语从句的时候后面不加n/pron的用法吗?