Children under six are not ____to school expect those of extraordinary intelligence.

您好！

Children under six are not __permit__to school expect those of extraordinary intelligence.

permit意为允许、准许

admit更偏向译为承认、供认

permit作动词意为“允许”“准许”＝allow someone to do or something to happen
permit to do
eg. I cannot permit this to happen.我不能允许此事发生。 The rules of the club do not permit alcohol.俱乐部规定不许饮酒。
permit作名词意为“许可证”

admit 动词 指（通常不情愿地）承认、供认
eg.Few politicians admit their mistakes.政客很少会承认自己的错误。 She will never admit that she is wrong.她绝对不会承认自己做错了。