zhēnzhèng de wèntí shì jīshuǐ.

Because 真正的 is modifying the noun 问题.

A very common pattern in Mandarin is:

modifier + 的 + noun

So here:

• 真正 = real / genuine / actual
• 的 = links the modifier to the noun
• 问题 = problem

So 真正的问题 means the real problem.

In English, we just put the adjective before the noun, but in Chinese, 的 often appears between them. With 真正, using 的 here sounds natural and standard.

Usually, no—not in normal everyday Mandarin.

真正的问题 is the natural form.
真正问题 sounds incomplete or unnatural in most contexts.

Chinese does sometimes omit 的 with certain modifiers, especially in fixed expressions or more compact/formal styles, but 真正 normally takes 的 before a noun.

So for learners, the safe rule is:

• 真正的问题 ✓
• 真正问题 ✗ / usually unnatural

Not quite.

• 真 often means true, real, or even really in some contexts.
• 真正 means genuine, real, the actual one, often with emphasis like the real / the true / the actual.

In this sentence, 真正的问题 means something like:

• the real problem
• the actual issue
• what the problem really is

So 真正 is a little more formal and precise than just 真.

是 is the verb to be, and here it links the topic and the explanation:

• 真正的问题 = the real problem
• 是 = is
• 积水 = standing water / water accumulation

So the structure is:

A 是 B = A is B

This sentence is identifying what the real problem is. That is exactly the kind of sentence where 是 is commonly used.

积水 refers to water that has collected in one place, usually because it has not drained away.

Common English translations include:

• standing water
• pooled water
• water accumulation

It is usually a noun in this kind of sentence.

Examples of where you might hear it:

• after heavy rain
• on roads
• in basements
• in low areas where water gathers

So 真正的问题是积水 means the main issue is not just rain in general, but specifically the water that has built up.

Yes, very similar in this sentence.

Chinese:

真正的问题 是 积水。

Literal order:

real problem is standing water

Natural English:

The real problem is standing water.

So this is a nice example where Mandarin and English line up quite closely.

Breakdown:

• 真正的 = real
• 问题 = problem
• 是 = is
• 积水 = standing water

Mandarin does not have articles like a, an, and the the way English does.

So 问题 can mean:

• a problem
• the problem
• problems

depending on context.

In this sentence, because of the overall meaning, 真正的问题 is understood as the real problem.

Chinese relies heavily on context instead of articles.

Grammatically, 问题 itself does not show singular or plural.

So by itself, 问题 could mean:

• problem
• problems

But in this sentence, the meaning is clearly singular: the real problem.

If you wanted to make it explicitly plural in another sentence, you would usually do that through context, numbers, or other wording—not by changing the noun itself.

For example:

• 一个问题 = one problem
• 几个问题 = several problems

Like this:

• 真正 — zhēnzhèng — first tone + fourth tone
• 的 — de — neutral tone
• 问题 — wèntí — fourth tone + second tone
• 是 — shì — fourth tone
• 积水 — jīshuǐ — first tone + third tone

A natural rhythm would be:

zhēnzhèng de wèntí shì jīshuǐ

A few pronunciation notes:

• 的 is light and unstressed.
• 问题 is pronounced wèn-tí, not wèn-tǐ.
• 积水 has a third tone on 水, so it dips.

Sometimes, but not always.

积水 specifically means water that has accumulated or standing water.
Flooding can be broader and often sounds more severe.

So:

• 积水 = pooled/collected water
• 洪水 = flood
• 淹水 / 水灾 = flooding / flood damage in some contexts

If the situation is just water collecting on the ground or road, standing water or water accumulation is often more accurate than flooding.

Yes, it sounds natural and clear.

It has a very normal structure:

真正的问题是 + noun

This pattern is common when someone wants to identify the core issue:

• 真正的问题是成本。
  The real problem is cost.
• 真正的问题是时间不够。
  The real problem is that there isn’t enough time.
• 真正的问题是积水。
  The real problem is standing water.

So this is a useful sentence pattern to remember.