N2 — outside your level filter

こと

ことkotoN2formal

savor + do — a rule or instruction set down in writing

ajiwau koto

do — a rule or instruction set down in writing

meaning: savor

使つかった道具どうぐは、必かならず元もとの場所ばしょに味あじわうこと。

tsukatta dougu wa, kanarazu moto no basho ni ajiwau koto.

Always savor tools you have used to the place they came from. formal

会場かいじょうでは、携帯けいたい電話でんわの電源でんげんを切きること。

kaijou de wa, keitai denwa no dengen o kiru koto.

Mobile phones are to be switched off inside the hall. formal

All examples6

do — a written instruction, in rules, notices, syllabuses and homework directions

使つかった道具どうぐは、必かならず元もとの場所ばしょに戻もどすこと。
tsukatta dougu wa, kanarazu moto no basho ni modosu koto.
Always return tools you have used to the place they came from. formal
会場かいじょうでは、携帯けいたい電話でんわの電源でんげんを切きること。
kaijou de wa, keitai denwa no dengen o kiru koto.
Mobile phones are to be switched off inside the hall. formal
レポートは金曜日きんようびの正午しょうごまでに提出ていしゅつすること。
repooto wa kin'youbi no shougo made ni teishutsu suru koto.
Reports are to be handed in by noon on Friday. formal

do not do — the same written instruction aimed at what is forbidden

見学中けんがくちゅうは、他ほかの人ひとから離はなれないこと。
kengakuchuu wa, hoka no hito kara hanarenai koto.
During the tour, do not leave the group. formal
実験室じっけんしつに飲のみ物ものを持もち込こまないこと。
jikkenshitsu ni nomimono o mochikomanai koto.
Drinks are not to be brought into the laboratory. formal
冷蔵庫れいぞうこのケーキ、勝手かってに食たべないこと！
reizouko no keeki, katte ni tabenai koto!
The cake in the fridge is not to be eaten without asking! casual

Written only; adding です (×切きることです) turns the rule back into
advice. Read aloud to someone, it sounds like reciting regulations.