zhèngfǔ zhèngzài diàochá zhège wèntí.

正在 shows that an action is in progress right now. In this sentence, it means the government is currently investigating the issue.

So:

• 调查这个问题 = investigate this issue / investigate this problem
• 正在调查这个问题 = be investigating this issue right now

It is similar to the English progressive idea in is investigating.

Yes. 政府调查这个问题 is grammatically fine, but it is more neutral and less specifically focused on the action being in progress at this moment.

Compare:

• 政府调查这个问题。 = The government investigates / is investigating this issue.
• 政府正在调查这个问题。 = The government is investigating this issue right now.

So 正在 makes the ongoing nature of the action clearer.

Here, 调查 is a verb, meaning to investigate.

In Chinese, many words can function as more than one part of speech depending on context. 调查 can also be a noun, meaning an investigation or a survey.

In this sentence:

• 政府 = subject
• 正在调查 = verb phrase
• 这个问题 = object

So here 调查 is definitely being used as a verb.

This follows the normal Chinese word order:

Subject + time/aspect marker + verb + object

So:

• 政府 = the government
• 正在 = currently / in the middle of
• 调查 = investigate
• 这个问题 = this issue

Chinese usually keeps a straightforward Subject–Verb–Object order, just like English, so this sentence is not unusual in structure.

Chinese does not have articles like a, an, and the.

So 政府 can mean:

• government
• the government

The exact meaning depends on context. In a sentence like this, English usually translates it as the government because that sounds natural.

这个 means this and is used to point out a specific thing:

• 这 = this
• 个 = a very common measure word

So 这个问题 means this question / this problem / this issue.

In Chinese, when using this or that before a noun, you usually need a measure word:

• 这个问题 = this issue
• 那个问题 = that issue

Even though 问题 is often translated as problem, it can also mean question or issue, depending on context.

Although 个 by itself is normally pronounced gè in the fourth tone, in 这个 it is very often pronounced with a neutral tone: zhège.

So in natural speech:

• 这个 → usually zhège

This is very common in everyday Mandarin. Learners should get used to common neutral-tone words and syllables, because they make speech sound more natural.

Yes. 问题 is a very common Chinese word with a broad meaning range. Depending on context, it can mean:

• question
• problem
• issue

In this sentence, issue or problem is usually the best translation, because the government is investigating it.

So:

• 这个问题 here is probably this issue or this problem
• not necessarily a literal spoken question

Yes, very often you can.

• 政府在调查这个问题。
• 政府正在调查这个问题。

Both can mean The government is investigating this issue.

The difference is that 正在 sounds a bit more explicit or formal about the action being in progress. 在 is also common as a progressive marker in modern spoken Mandarin.

Very roughly:

• 在 + verb = doing
• 正在 + verb = right in the middle of doing / currently doing

Yes, it is both natural and somewhat formal/neutral in tone.

Because of words like:

• 政府 = government
• 调查 = investigate
• 问题 = issue/problem

the sentence sounds like something you might see in:

• news reports
• official statements
• formal writing

It is still perfectly normal Mandarin, not unnatural or overly literary.

Usually, no. That would not sound right in normal Mandarin for this meaning.

正在 already marks the action as ongoing, so adding sentence-final 了 here would usually create a clash or at least sound odd without a special context.

The natural sentence is:

• 政府正在调查这个问题。

If you want to say the investigation has started, you might say something like:

• 政府开始调查这个问题了。 = The government has started investigating this issue.

So beginners should remember: 正在 and 了 do not usually go together in a simple sentence like this.