to betray someone who trusts you
背叛信任你的人 (bèi pàn xìn rèn nǐ de rén)
"I can’t believe he stabbed me in the back after all I did for him."
"我简直不敢相信他在我为他做了这么多之后竟然在背后捅了我一刀。" (Wǒ jiǎnzhí bù gǎn xiāngxìn tā zài wǒ wèi tā zuòle zhème duō zhīhòu jìngrán **zài bèihòu tǒngle wǒ yī dāo**.)
it's not difficult to understand
to use authority to make people work harder or obey rules
past one's prime; no longer young or at peak performance
to cause harm or damage over time due to stress or overwork
to have an advantage or be well prepared
to have an extremely enjoyable experience
