Placodium
产囊原基层, 囊壳孔口处的硬皮层
🗣️ 情景例句
Is it supposed to rain today?
今天要下雨吗？
How long will you be working in Canada?
你将在加拿大工作多久？
who rolled balls down inclined planes,
他就是那个使球体沿斜面向下滚动，