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
The economy is booming in this country.
这个国家的经济形势一片大好。
I'm sorry I'm late. I overslept again.
抱歉我来晚了。我又睡过头了。
'You needn't be so rude about it,' my wife answered as she looked at herself in the mirror.
“你说话没必要这样不客气，”我的妻子边回答边照着镜子。