三人行，必有我师(焉)

成语
迷途知返 to mend one's ways, to get back on the right path
可想而知 as one can easily imagine
除恶务尽 to eradicate evil completely
( ”pinyin” )

词汇
毛, hair/fur/0.1 yuan (?); 毛病, trouble (pinyin in tags)
https://mandarinbean.com/new-hsk-3-word-list/

Guardian:
迷途知返为时不晚, it's not too late to mend your ways
他的近况也就可想而知, you can imagine how he's doing now
我也没想到因为他母亲的死让他后来转成除恶务尽的作风, I never thought that his mother's death would later make him decide to eradicate all evil
不准你伤他一根毫毛, don't you dare harm a single hair of him!

Me:
可想而知，冬天起床不容易。
他的睫毛很长。

Will stick to the current chengyu practice for at least a little while. (If you are thinking "wait, I come here for the grammar, where is it," comment or DM me and I'll see what I can do.)

成语
三番五次 over and over again (lit. three times, five times)
兵贵神速 swift and resolute (lit. speed is important in war)
一无所知 not having a clue, completely ignorant
( pinyin )

词汇
租, 出租, rent; 出租车, taxi (pinyin in tags)
https://mandarinbean.com/new-hsk-2-word-list/

Guardian:
你三番五次地来打扰我工作，你这让我很为难, you're giving me great trouble by coming to disturb my work so many times
兵贵神速，我们这不也是害怕再有学生遇害嘛, speed is of the essence, aren't we all worried that another student will be harmed?
你对我的电力一无所知, you don't know a thing about my electrical power
这婚纱租一天不少钱呢, it cost a lot to rent this wedding dress for a day

Me:
我三番五次地跟你说过，睡觉之前要关电灯。
房租这个公寓多少钱？

语法
不到 + time + 就 + ～～ “less than X time" (bottom of page)
https://resources.allsetlearning.com/chinese/grammar/Expressing_%22less_than%22_with_%22budao%22

词汇
知道, know; 知识, knowledge ( pinyin )