D-layer
n. D层（电离层的最下层）
🧩 词语组成解析
layer
['leiə]
n. 层，层次;膜;[植]压条;放置者，计划者;
vt. 把…分层堆放;借助压条法;生根繁殖;将（头发）剪成不同层次;
vi. 形成或分成层次;[植]通过压条法而生根;
🗣️ 情景例句
Yes, but I don't know where to start.
是的 ，但我不知道从何说起。
Fortune to one is mother, to another is stepmother.
命运对一种人如亲娘，对另一种人却是晚娘。
as if he were holding it completely enclosed in the hollow of his hand.
就好像完全握在自己手心里一样。