Back mutation
回复突变
🧩 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
Lacks confidence and poise is nervous and ill at ease.
信心不足，不够自信，精神紧张，心神不定。
I asked him to paint it for me, but he wouldn't
我请他帮我油漆，但是他不肯。
It's against the rules to handle the ball in soccer.
在足球中以手触球就是犯规。