taapu wo soto ni oku.

タープ is a loanword from English tarp or tarpaulin. It is written in katakana because katakana is commonly used for foreign loanwords in Japanese.

So:

• タープ = tarp

Katakana often signals that the word was borrowed from another language.

The particle を marks the direct object of the verb.

In this sentence:

• タープを = the tarp as the thing being placed

So を tells you that タープ is the thing affected by 置く.

Pattern:

• noun + を + verb

Examples:

• 本を読む = read a book
• 荷物を置く = put down luggage

The particle に marks the destination or target location where something is placed.

In this sentence:

• 外に置く = put it outside

With verbs like 置く, に often marks the place where something ends up.

Compare:

• 机の上に置く = put it on the desk
• 外に置く = put it outside

So here に answers the question where is the tarp being placed?

Because 置く is about putting something into a location, Japanese usually uses に for the place where the object is placed.

• に = target location / resulting location
• で = place where an action happens

With 置く, the important idea is where the object ends up, so に is the natural choice.

• 外に置く = put it outside

Using で here would sound unnatural in normal Japanese.

They are read:

• 外 → そと
• 置く → おく

So the whole sentence is read:

• タープをそとにおく。

A helpful note: this おく is the verb 置く, meaning to place / to put. It is different from the helper verb 〜ておく, which also sounds like おく but has a different grammar function.

置く is in the dictionary form (also called the plain non-past form).

That form can mean different things depending on context, such as:

• to put
• put / will put
• puts

So by itself, タープを外に置く。 could be understood as a plain statement like:

• I put the tarp outside
• I will put the tarp outside
• Put the tarp outside

The exact nuance depends on context. On its own, it is a plain, non-polite form.

Yes. Japanese often leaves out the subject when it is understood from context.

So even though English usually wants something like I, you, or we, Japanese often does not say it if it is obvious.

For example, this could mean:

• I put the tarp outside
• We put the tarp outside
• Put the tarp outside

The listener figures it out from the situation.

It can mean all of those depending on context, but its core meaning is to place / to put something somewhere.

Common translations:

• put
• place
• set down
• leave

For example:

• 荷物を置く = put down luggage
• 外に置く = leave it outside / put it outside

So 置く often focuses on the result that something is now sitting in a certain place.

外 by itself very commonly means outside.

In everyday Japanese:

• 外 = outside
• 外に = to/outside
• 外で = outside, at an outside location

外側 means something more like the outer side / exterior side, so it is a different nuance. For simply saying outside, 外 is the normal word.

No. Normal Japanese writing usually does not use spaces between words.

This sentence would normally be written as:

タープを外に置く。

Spaces are often added in textbooks or beginner materials to make the structure easier to see.

No. This is plain form, not polite form.

The polite version would be:

• タープを外に置きます。

So:

• 置く = plain
• 置きます = polite

Plain form is very common in casual speech, dictionary entries, and simple example sentences.