Back cover
后壳，后罩
🧩 词语组成解析
back
[bæk]
n. 背，背部;背面，反面;后面，后部;（椅子等的）靠背;
vt. 使后退;支持;加背书于;下赌注于;
vi. 后退;倒退;
adj. 背部的;后面的;以前的;拖欠的;
adv. 以前;向后地;
🗣️ 情景例句
Do you happen to know...
你是否碰巧知道…
It's been cloudy all morning.
整个早上多云。
it was not long before its use as the uniquely recognizable broadcasting frequency for interstellar communication was suggested.
提出把它作为星际间唯一可辨认的广播频率就为期不远了。