Peridentalt
牙週組織
??? 情景例句
No, you needn't do that.
不行呀，你不必這樣。
Parents usually put a small red paper packet under their child's pillow.
父母常常會(huì)在孩子枕頭下放一個(gè)小紅包。
and that this happens at a rate which differs little from person to person,
衰老的速度在人與人之間相差甚微，