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
Having their origins in China, chopsticks are used in many Asian countries.
筷子起源于中国，现在很多的亚洲国家都使用它。
What shall I send him for his birthday?
我要送他什么东西作为生日礼物？
Are all the things in the car now?
现在所有的东西都在车上吗？