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
Is he still in his office?
他还在办公室吗？
Look before you leap; see before you go.
三思而行。
No, he didn't want to leave.but his wife did!
是啊，他是不想离开，可是他妻子要离开。