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[化] 反馈作用
🧩 词语组成解析
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[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
Sounds of the country.
乡村音响。
Would it be too much to ask you to respond to my question by tomorrow?
可以请你在明天以前回复吗？
The young man did not wake up until the bed had struck the ground.
那年轻人直到床撞到地上才醒了过来。