三人行，必有我师(焉)

Thank you for kind and useful comments yesterday! Replies/further discussion to follow, today a bit of a rush.

语法
Causatives 由 and 将 + "since" (I don't know why 自从 is in the same lesson)
https://mandarinbean.com/you2/
https://resources.allsetlearning.com/chinese/grammar/Using_%22jiang%22_as_a_formal_%22ba%22
https://resources.allsetlearning.com/chinese/grammar/Emphasizing_the_doer_of_an_action_with_%22you%22
https://resources.allsetlearning.com/chinese/grammar/Expressing_%22ever_since%22_with_%22zicong%22

词汇
落后, backward (pinyin in tags)
https://mandarinbean.com/new-hsk-3-word-list/

Guardian:
老板的任务一直都是由你负责, the boss' duties have been for you to handle all along
城东区树林将全部被砍伐, the forest in the eastern district will all be cut down
自从你当年离我而去，我就戴上了这个面具, I have worn this mask since you left me back then
[no 落后]

Me:
自从昨天我们在第四年中.
不要走得落后了，你肯定要摔倒了。