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
Smoking will kill you.
吸烟会害了你。
Must be.
一定是。
The gaoler looked on eagerly, anxious to see if his fellow actor had at last learnt his lines.
狱卒热切地观察着，急于想了解他的同事是否记熟了台词。