Why is it that we are at sixes and sevens about the one thing human beings have been doing successfully for millennia, long before parenting message boards and peer-reviewed studies came along?
这可是一件人类 薪火相传了上千年的事情， 为何今天却让人摸不着头脑呢？ 那时，可没有育儿论坛， 也没有专家特地来研究。