watasitati ha sinpaisosei wo rensyuusuru.

A natural reading is:

わたしたち は しんぱいそせい を れんしゅうする。

In rōmaji:

Watashitachi wa shinpai sosei o renshū suru.

A few notes:

• は is written ha but pronounced wa when it marks the topic.
• を is often pronounced o.

私たち means we.

• 私 = I / me
• たち added to a person word makes it plural or group-like

So:

• 私 = I
• 私たち = we

English requires a subject like we, but in Japanese, 私たち is often omitted if it is clear from context.

は marks the topic of the sentence.

So 私たちは means something like:

• As for us, ...
• We, ...

In many beginner translations, it is easiest to think of it as marking the subject, but technically it marks the topic, not always the grammatical subject.

Here, 私たちは 心肺蘇生を 練習する means:

• As for us, we practice CPR

This is a special rule for the particle は.

• As a normal syllable, は is read ha
• As the topic particle, it is pronounced wa

So in this sentence:

• written: 私たちは
• pronounced: わたしたち は (wa)

This is just something you memorize for particles.

心肺蘇生 is the Japanese term for cardiopulmonary resuscitation (CPR).

The kanji parts are:

• 心 = heart
• 肺 = lungs
• 蘇生 = revival / resuscitation

So the literal idea is heart-lung resuscitation, which corresponds to CPR in English.

を marks the direct object of the verb.

The verb here is 練習する = to practice.

So:

• 心肺蘇生を練習する = to practice CPR

You can think of を as showing what is being practiced.

Japanese sentences usually put the main verb at the end.

So the order here is:

• 私たち = we
• は = topic marker
• 心肺蘇生 = CPR
• を = object marker
• 練習する = practice

This is a very normal Japanese pattern: Topic + object + verb

That is why the sentence ends with 練習する.

練習する is a suru-verb.

• 練習 means practice as a noun
• する means to do

Together:

• 練習する = to practice

This pattern is very common in Japanese:

• 勉強する = to study
• 運動する = to exercise
• 掃除する = to clean

So here, 心肺蘇生を練習する literally feels like do practice of CPR.

Yes. That would be the polite form.

• 練習する = plain form
• 練習します = polite form

So:

• 私たちは心肺蘇生を練習する。
  plain style; often used in writing, explanations, dictionary style, or casual contexts

• 私たちは心肺蘇生を練習します。
  polite style; common in conversation and formal situations

The basic meaning is the same.

It can often be omitted.

Japanese frequently leaves out subjects and topics when they are understood from context. So in many situations, you could simply say:

心肺蘇生を練習する。

That still means We practice CPR, I practice CPR, or even (someone) practices CPR, depending on context.

Japanese relies heavily on context, much more than English does.

In real life, many people also say CPR in Japanese, especially in medical or emergency-related contexts.

You may hear:

• 心肺蘇生
• CPR
• sometimes 心肺蘇生法 in more formal or instructional language

But 心肺蘇生 is a correct and standard Japanese term.

Usually 私たち just means we / us, but exactly who is included depends on context.

It might mean:

• I and some other people
• all of us here
• a group the speaker belongs to

Japanese does not always clearly mark the difference between:

• we including you
• we excluding you

So you usually understand the group from the situation.

Japanese does not use articles like a, an, or the.

So 心肺蘇生 can mean:

• CPR
• the CPR
• cardiopulmonary resuscitation

The exact nuance comes from context, not from an article.

That is normal in Japanese.

Yes, that is also possible.

Compare:

• 心肺蘇生を練習する
• 心肺蘇生の練習をする

Both mean roughly to practice CPR.

The second version is more literally:

• to do practice of CPR

Breakdown:

• 心肺蘇生の練習 = CPR practice
• をする = do

Both are grammatical. The original sentence is compact and natural.

練習する is the plain non-past form.

In Japanese, the non-past form can mean:

• present habitual: we practice CPR
• future: we will practice CPR

So this sentence could mean either, depending on context.

Examples:

• habitual: We practice CPR every week.
• future: We will practice CPR tomorrow.

Japanese often leaves the exact time reference to context or time words.

Yes, it is grammatical and understandable.

That said, in everyday speech, a speaker might more often say:

• 私たちは心肺蘇生を練習します。 if speaking politely
• 心肺蘇生を練習する。 if the subject is already understood

So the given sentence is fine, but whether it sounds most natural depends on context and level of formality.