atarasii sinsitu ni tansu wo oite, siroi siitu wo beddo ni kakemasita.

Because 新しい is an い-adjective. In Japanese, い-adjectives can directly modify a noun:

• 新しい寝室 = a new bedroom

You do not use の between an い-adjective and a noun.

Compare:

• 新しい寝室 = a new bedroom
• きれいな寝室 = a clean/pretty bedroom

In the second example, きれい is a な-adjective, so it needs な before the noun.

Here, に marks the place where something is put or placed.

• 寝室にタンスを置いて = put a dresser in the bedroom

With verbs like 置く (to place / to put), に often shows the destination or resulting location of the object.

So:

• 寝室に = in/into the bedroom

It is not the object of the verb; it is the location where the dresser ends up.

を marks the direct object of the verb — the thing being acted on.

In this sentence:

• タンスを置いて = placed the dresser
• 白いシーツをベッドにかけました = put/spread the white sheet on the bed

So the objects are:

• タンス
• 白いシーツ

These are the things the speaker is physically moving or handling.

置いて is the て-form of 置く. It is used here to link two actions in one sentence.

So the structure is:

• タンスを置いて、
• 白いシーツをベッドにかけました。

This means something like:

• I put the dresser in the new bedroom, and then put a white sheet on the bed.

Only the final verb, かけました, is marked for past polite tense, but the whole sentence is understood as a sequence of completed actions.

This is very common in Japanese:

• Aて、Bました = did A, and then did B

Yes, in this sentence it strongly suggests a sequence:

1. put the dresser in the new bedroom
2. put the white sheet on the bed

The て-form often links actions that happen one after another.

So 置いて、かけました is naturally read as:

• placed it, then spread/put it

Depending on context, the て-form can sometimes mean other things too, but in a sentence like this, sequential action is the most natural reading.

Here に marks the target surface/place that the sheet is being put onto.

• ベッドにかけました = put/spread it on the bed

With かける, に often marks what something is applied to, hung on, draped over, or placed onto.

So:

• シーツを = the sheet (thing being placed)
• ベッドに = onto the bed (target)

This is different from English structure, so it can feel unusual at first.

かける has several meanings, and one common one is to hang, to put over, to drape, or to spread over something.

In this sentence, it does not mean hanging a sheet from a hook or clothesline. It means something more like:

• put a sheet on the bed
• spread a sheet over the bed

So 白いシーツをベッドにかけました means the speaker placed or spread the white sheet onto the bed.

This is a good example of how one Japanese verb can cover several related English verbs depending on context.

Because Japanese often omits the subject when it is clear from context.

So instead of saying:

• I put a dresser in the new bedroom and put a white sheet on the bed

Japanese can simply say:

• 新しい寝室にタンスを置いて、白いシーツをベッドにかけました。

The subject might be:

• I
• we
• someone already being talked about

Japanese leaves it unstated unless it needs to be emphasized or clarified.

タンス means a dresser, chest of drawers, or sometimes a clothes cabinet, depending on context.

It is often written in katakana in modern Japanese, even though the word is not just a recent English loanword. The kanji form is 箪笥, but that is much less common in everyday writing.

So in this sentence, タンス is a piece of bedroom furniture.

Yes, it is natural, but Japanese may express this idea in a few different ways depending on exactly what is meant.

• シーツをベッドにかける = put/spread a sheet over the bed
• ベッドにシーツを敷く = lay a sheet on the bed

A learner may notice that 敷く is also possible. The difference is nuance:

• かける focuses on putting something over/onto
• 敷く focuses on laying something flat

In many simple learning examples, かける works fine for describing putting bedding onto a bed.

Japanese word order is usually built around particles, not fixed English-style position.

In this sentence:

• 新しい寝室に = in the new bedroom
• タンスを = the dresser
• 置いて = put, and...
• 白いシーツを = the white sheet
• ベッドに = on the bed
• かけました = put/spread

Japanese often places:

• locations before the verb
• objects before the verb
• the main verb at the end

So even though the order feels different from English, the particles に and を clearly show each word’s role in the sentence.