we all insisted that we ________until we finished the work.

we all insisted that we ________until we finished the work.
a.would't rest b.won't rest c.didn't rest d.not rest
我选了a,我知道insist that sb.should （not） do,请问为何不选d?
insist that sb.should （not） do的结构中insist解释为什么意思？求具体用法和例句
insist that sb.should （not） do不就是虚拟语气吗，为什么有解答说“一般现在式虚拟语气动词用过去式”？