siken no toki ha, enpitu wo nihon motte iku you ni site imasu.

試験のとき means when it is exam time, at the time of an exam, or more naturally, during an exam / when taking an exam depending on context.

The の links 試験 and とき:

• 試験 = exam
• とき = time, occasion

So:

• 試験のとき = the time of the exam / when there is an exam

This is a very common pattern:

• 子どものとき = when I was a child
• 日本に行くとき = when going to Japan
• 忙しいとき = when busy

So here, の is acting like of or a linking particle between the noun and とき.

The は marks 試験のとき as the topic of the sentence.

So the sentence has the feeling of:

• As for exam time, I make a point of taking two pencils.

It can also suggest a mild contrast, depending on context:

• At exam time, I do this.

That can imply something like:

• maybe not in other situations
• but specifically for exams, this is my habit

So は is not just marking time; it is setting the scene and making during exams the topic.

Both are possible, but they do slightly different jobs.

• ときに focuses more on the time point: at the time when...
• ときは makes it the topic: when it comes to... / as for when...

Compare:

• 試験のときに、鉛筆を二本持っていきます。
  = I take two pencils at exam time.

• 試験のときは、鉛筆を二本持っていくようにしています。
  = When it’s exam time, I make a point of taking two pencils.

In your sentence, は works well because the speaker is talking about a general habit or policy for exam situations.

Both word orders can be seen, but 鉛筆を二本 is very standard and natural.

The structure is:

• 鉛筆を = pencils as the object
• 二本 = two long cylindrical objects

Japanese counters often come:

• after the noun with the particle before the counter, or
• before the noun in some expressions

So these are both possible:

• 鉛筆を二本持っていく
• 二本の鉛筆を持っていく

The first one is very common in everyday Japanese.

Japanese uses different counters depending on the shape or type of object.

本 is used for long, thin, cylindrical objects, such as:

• pencils
• pens
• bottles
• umbrellas

So:

• 鉛筆一本 = one pencil
• 鉛筆二本 = two pencils
• 鉛筆三本 = three pencils

A native English speaker often wants to use a general counter like つ, but for something like pencils, 本 is the normal choice.

It is read にほん.

For the counter 本, the reading changes depending on the number:

• 一本 = いっぽん
• 二本 = にほん
• 三本 = さんぼん

This happens because of sound changes that are very common with counters.

So in this sentence:

• 鉛筆を二本 = えんぴつ を にほん

持つ means to hold, to carry, or to have.

持っていく means to take something somewhere.

In this sentence, the speaker is not just saying I have two pencils. They are saying they take two pencils to the exam.

So:

• 鉛筆を二本持つ = to hold/have two pencils
• 鉛筆を二本持っていく = to take two pencils along

Even though the destination is not explicitly stated, it is understood from 試験のとき.

This depends on the direction of movement from the speaker’s point of view.

• 持っていく = take something away from here / along to somewhere
• 持ってくる = bring something to here / toward the relevant place

In this sentence, the speaker is thinking of taking pencils along when going to an exam, so 持っていく is natural.

If the situation were centered on the exam place or on the listener being there, 持ってくる might be used in another context. But here, 持っていく fits the usual idea of bringing along/taking with me.

No, it is softer and has a special nuance.

V dictionary form + ようにしています means:

• I make an effort to...
• I try to...
• I make it a habit to...

So:

• 持っていくようにしています
  = I make a point of taking them
  = I try to take them
  = I have a habit of taking them

This is different from plain 持っていきます, which would simply mean:

• I take them / I will take them

The ようにしています part adds the idea of intentional habit or personal rule.

In this pattern, ようにする is a set grammar pattern.

Structure:

• verb dictionary form + ようにする
• verbない form + ようにする

It means to make an effort to do something or to make sure to do something.

Examples:

• 毎日日本語を勉強するようにしています。
  = I try to study Japanese every day.

• 夜はコーヒーを飲まないようにしています。
  = I try not to drink coffee at night.

So the に is just part of this established grammar pattern. It is not the usual destination に or time に.

Not necessarily.

In many cases, 〜ています does not mean something is happening right now. It can also describe:

• a habitual action
• an ongoing state
• a repeated practice

Here, ようにしています means the speaker has this habit / keeps this policy.

So the sentence does not mean:

• I am currently, at this moment, making an effort...

It means:

• This is what I generally do.
• This is my usual practice when there’s an exam.

Usually it sounds like a personal habit or precaution, not a strict official rule.

〜ようにしています often suggests:

• a conscious habit
• something the speaker tries to do regularly
• a personal policy

So the nuance is something like:

• I make sure to take two pencils for exams.
• I try to take two pencils when I have an exam.

It sounds practical, like the speaker wants to be prepared.

Yes, you could, but the nuance changes.

• 鉛筆を二本持っていきます。
  = I take two pencils. / I will take two pencils.

This is more direct and neutral. It can refer to:

• a regular action, depending on context

• or a future action

• 鉛筆を二本持っていくようにしています。
  = I make a point of taking two pencils.

This emphasizes:

• habit
• intention
• personal practice

So the original sentence is better if the speaker wants to express a routine they deliberately follow.