Placodium
产囊原基层, 囊壳孔口处的硬皮层
🗣️ 情景例句
You don't know up from down.
你黑白不分。
A new bicycle is out of the question - we can't afford it.
买新自行车的事谈不上 —— 我们买不起。
Mrs.Ramsay received an anonymous letter.
拉姆齐太太收到一封匿名信。