Injective
[計] 內射, 單射
??? 情景例句
No. I'm sorry, but we can't send out our tow truck to get you.
不能，真對不起，我們不能派拖車來。
He who risks nothing, gains nothing.
不入虎穴，焉得虎子。
What a coincidence!
真是太巧了。