忘れ物をしないようにしてください。
- Please make sure you don’t leave anything behind.

忘れ物をしないようにしてください。 meaning: Please don't forget your belongings.

The sentence 忘れ物をしないようにしてください。 is a polite request or instruction. It breaks down as follows: ⚫︎ 忘れ物(wasuremono): "Lost item(s)" or "things left behind." It's a noun. ⚫︎ を(o): The direct object particle. Marks 忘れ物 as the thing being "forgotten." ⚫︎ する(suru): "To do." This is the verb that describes the action. In this context, it takes on the meaning of "to make" or "to commit." ⚫︎ ない(nai): The negative form of the verb する(suru), meaning "not do" or "not to commit." The verb has been changed to its negative form. ⚫︎ ように(you ni): This is a crucial phrase. It means "so that," "in order to," or "in a way that." It indicates purpose or a desired outcome. ⚫︎ して(shite): This is the "-te" form of the verb する(suru), which is used for various grammatical functions, including connecting phrases. ⚫︎ ください(kudasai): This is the polite form of the verb ください(kudasai), meaning "please." It indicates that the speaker is making a request. Essentially, the sentence is structured to communicate "Please do [not commit/do] the action of forgetting your belongings, in a way that [you don't]."

The sentence pattern ～ように (you ni) is used to express purpose, intention, or a way of doing something. ⚫︎ The basic form is: [Verb (dictionary form) + ように] or [Verb (nai-form) + ように]. ⚫︎ In this sentence, it's used with the negative form of the verb, indicating the desired outcome: not forgetting. ⚫︎ Example: 健康のために、毎日運動します。(Kenkou no tame ni, mainichi undou shimasu.) - I exercise every day in order to be healthy. ⚫︎ Example: 道に迷わないように、地図を見ます。(Michi ni mayowanai you ni, chizu o mimasu.) - I look at the map so that I don't get lost.

The negative form of verbs (the "nai-form") is essential for constructing sentences like this. ⚫︎ To make the negative form: ⚫︎ For グループ１ verbs (verbs that end with -u): Change the -u ending to -anai. ⚫︎ Example: 食べる(taberu, to eat) becomes 食べない(tabenai, not to eat). ⚫︎ For グループ２ verbs (verbs that end with -eru or -iru): Drop the -ru and add -nai. ⚫︎ Example: 見る(miru, to see) becomes 見ない(minai, not to see). ⚫︎ For irregular verbs: ⚫︎ する(suru, to do) becomes しない(shinai, not to do). ⚫︎ 来る(kuru, to come) becomes 来ない(konai, not to come). ⚫︎ The sentence uses the negative form しない(shinai) of する(suru).

The auxiliary verb ください (kudasai) is a polite request or command form. ⚫︎ It is placed at the end of a sentence and makes it a request. ⚫︎ The structure is: [Verb (e.g., -te form) + ください]. ⚫︎ ください changes the verb's form into a polite imperative. ⚫︎ Example: 食べてください。(Tabete kudasai.) - Please eat. ⚫︎ Example: 座ってください。(Suwatte kudasai.) - Please sit down. In the example sentence, して(shite), the -te form of the verb する(suru), is followed by ください(kudasai) to form a polite request.

The particle を (o) marks the direct object of a verb. ⚫︎ The direct object is the thing that the action of the verb is performed upon. ⚫︎ It's usually placed after the noun that is the direct object. ⚫︎ Example: 本を読みます。(Hon o yomimasu.) - I read a book. 本(hon, book) is the direct object of the verb 読みます(yomimasu, read), so it is followed by を(o). ⚫︎ In this sentence, it connects to 忘れ物(wasuremono), which is the direct object of the implied action of "forgetting."