Kakak perempuan saya membersihkan rak itu bukan karena takut tikus, melainkan karena dia tidak mau rayap datang lagi.

Kakak means older sibling, without necessarily stating gender.

So:

• kakak saya = my older sibling
• kakak perempuan saya = my older sister

In everyday Indonesian, people often just say kakak saya if the gender is already clear from context. Adding perempuan makes it fully explicit.

Membersihkan means to clean or to make something clean.

It comes from the root bersih = clean.

The pattern is:

• bersih = clean
• membersihkan = to clean something

The suffix -kan often makes the verb clearly transitive, meaning it takes a direct object. Here, the object is rak itu.

So:

• Dia membersihkan rak itu = She cleaned the shelf

Membersih is not the normal form here.

In Indonesian, demonstratives like ini and itu usually come after the noun.

So:

• rak itu = that shelf
• buku ini = this book
• rumah itu = that house

This is a very common word order difference from English.

This pattern is used to contrast two explanations:

• bukan karena X, melainkan karena Y
• not because of X, but rather because of Y

It sounds more formal and precise than a simple tetapi structure.

So the sentence is saying:

• the reason was not fear of mice,
• but rather the fact that she did not want termites to come again.

This structure is common when correcting an assumption.

In Indonesian, bukan is usually used to negate:

• nouns
• noun phrases
• prepositional phrases
• clauses of identification/contrast

Tidak is usually used to negate:

• verbs
• adjectives

Here, karena takut tikus is being treated as the reason phrase being rejected, so bukan is the natural choice:

• bukan karena takut tikus = not because she was afraid of mice

Using tidak karena would sound unnatural here.

Indonesian often does not need a separate word for of after takut.

So:

• takut tikus = afraid of mice
• takut anjing = afraid of dogs

You may also hear forms like:

• takut pada tikus
• takut sama tikus

But in many cases, just takut + noun is perfectly natural.

They are two different animals/pests:

• tikus = mouse / rat
• rayap = termite

English separates mouse and rat, but Indonesian commonly uses tikus for both unless there is a reason to be more specific.

Rayap specifically means termite, especially in contexts involving wood damage, furniture, shelves, and houses.

Yes, tidak mau literally means does not want.

But in sentences like this, it often has the sense of:

• doesn’t want to
• doesn’t want X to happen
• doesn’t want to let X happen

So:

• dia tidak mau rayap datang lagi

means something like:

• she didn’t want termites to come again
• she didn’t want the termites coming back again

It expresses intention or unwillingness to allow that situation.

Both can work, but lagi is very common in everyday Indonesian.

• datang lagi = come again / come back again
• kembali = return / again, often a bit more formal or neutral depending on context

So:

• rayap datang lagi sounds natural and conversational
• rayap kembali datang is also possible, but a little less everyday in tone

Indonesian often repeats a pronoun even when the subject is already clear.

So after saying kakak perempuan saya, it is completely normal to continue with dia:

• ... melainkan karena dia tidak mau ...

This helps make the second clause sound complete and natural.

Indonesian can sometimes omit subjects when they are obvious, but including dia is very common and often clearer.

The subject does not always have to be repeated, but repeating it or using dia is often the most natural choice in a longer sentence.

For example:

• Kakak perempuan saya membersihkan rak itu bukan karena takut tikus, melainkan karena tidak mau rayap datang lagi.

This is understandable, but many speakers would prefer the version with dia because it is clearer and flows better in a contrastive sentence.

A useful breakdown is:

• Kakak perempuan saya = subject
• membersihkan = verb
• rak itu = object
• bukan karena takut tikus = rejected reason
• melainkan karena dia tidak mau rayap datang lagi = actual reason

So the pattern is:

Subject + verb + object + not because X, but rather because Y

This is a very useful model for building similar Indonesian sentences.

It is mostly neutral, with one slightly formal feature:

• melainkan sounds a bit more formal or polished than tetapi or tapi

Everything else is quite standard and natural.

A more casual version might be:

• Kakak perempuan saya membersihkan rak itu bukan karena takut tikus, tapi karena dia tidak mau rayap datang lagi.

That version is a little more conversational.