yīshēng shuō, rúguǒ jīntiān wǎnshang yòu fāshāo, jiù gǎnjǐn lái yīyuàn.

Chinese often omits subjects when they are obvious from context.

In this sentence, the doctor is clearly speaking to a specific person, so 你 is understood:

• 如果你今天晚上又发烧，你就赶紧来医院。

But in natural speech, repeating 你 is often unnecessary, so it gets dropped.

又 means again.

So 又发烧 means get a fever again or have a fever again.

It suggests the person has already had a fever before, and the doctor is talking about it happening one more time tonight.

This is a very common question.

Both 又 and 再 can relate to repetition, but they are used differently:

• 又 often refers to something happening again, especially when it has already happened before and the speaker sees it as a repeated event.
• 再 is more commonly used for doing something again in the future.

Here, 又发烧 sounds natural because the doctor is talking about the return of a symptom the patient has already had.

A learner-friendly way to think about it:

• 又 = again, as a repeated situation
• 再 = again, one more time in the future

In real life, this distinction is not always perfectly simple, but in this sentence 又发烧 is very natural.

就 marks the result or action that follows the condition.

Pattern:

• 如果 A，就 B
• if A, then B

So here:

• 如果今天晚上又发烧，就赶紧来医院。
• If you get a fever again tonight, then come to the hospital right away.

In English, then is often optional, and in Chinese 就 is also sometimes omitted, but it is very common and makes the conditional relationship clearer.

Chinese time expressions usually go from larger time unit to smaller time unit.

So:

• 今天 = today
• 晚上 = evening / night

Together:

• 今天晚上 = tonight / this evening

This big-to-small order is normal in Chinese:

• 今天上午 = this morning
• 明天下午 = tomorrow afternoon
• 星期五晚上 = Friday night

发烧 is usually used as a verb in everyday Chinese.

It means to have a fever.

So Chinese says:

• 我发烧了。
• I have a fever.

It does not need a separate verb like have in English.

That is why 又发烧 directly means get a fever again / have a fever again.

This is about point of view.

• 来 = come
• 去 = go

Chinese chooses between them based on the speaker’s reference point.

Since the doctor is speaking from the hospital’s perspective, 来医院 means come to the hospital.

If someone outside the hospital were talking about it, they might say:

• 去医院 = go to the hospital

So in this sentence, 来 sounds natural because the destination is the doctor’s location or side.

赶紧 means quickly, at once, or without delay.

It has a stronger feeling than simply doing something fast. It suggests urgency:

• 赶紧来医院 = come to the hospital right away

It is very common in spoken Chinese and often used when giving advice, warnings, or urgent instructions.

It is functioning like reported speech, and Chinese is often flexible about this.

• 医生说，……
• The doctor said, ...

What follows is the content of what the doctor said. Chinese does not always clearly separate direct and indirect speech the way English does with quotation marks and tense changes.

So you can think of it simply as:

• The doctor said: If you get a fever again tonight, come to the hospital right away.

The commas help show the structure of the sentence.

• 医生说， introduces what the doctor said
• 如果今天晚上又发烧， is the condition
• 就赶紧来医院。 is the result / instruction

So the sentence breaks naturally into:

1. reporting clause
2. if-clause
3. main action

Chinese punctuation is very useful for spotting these chunks.

Yes, that is grammatically correct.

Adding 你 makes the subject explicit:

• 如果你今天晚上又发烧，你就赶紧来医院。

But the original version is more natural if the listener is obvious from context. Chinese often prefers the shorter version.

So:

• with 你 = clearer, slightly more explicit
• without 你 = more natural in many real conversations

Yes, in everyday speech 晚上 is usually pronounced:

• wǎnshang

The second syllable 上 is often neutral here.

So although 上 normally has a fourth tone when used alone (shàng), in 晚上 it is commonly pronounced lightly as shang.

That is very normal.

Yes.

• 今晚 = tonight
• 今天晚上 = tonight / this evening

Both are correct.

今晚 is shorter and a little more compact, while 今天晚上 is slightly fuller and very common in speech.

So you could also say:

• 医生说，如果今晚又发烧，就赶紧来医院。

That sounds natural too.

No.

After the verb 来, the place can come directly:

• 来医院 = come to the hospital

Chinese does not need a word like to here. The direction is understood from the verb.

So:

• 来医院
• literally: come hospital
• natural meaning: come to the hospital

This is very normal Chinese sentence structure.

The second part is basically an instruction or urgent advice.

• 就赶紧来医院。
• then come to the hospital right away

It is not as blunt as a pure order in English can sound. In context, it is medical advice from a doctor, so it naturally comes across as strong guidance.

So the whole sentence is:

• a reported statement from the doctor
• containing a condition + instruction

A useful pattern here is:

• A 说，如果……，就……
• Someone says that if ..., then ...

More specifically:

• 医生说， = the doctor said
• 如果今天晚上又发烧， = if you get a fever again tonight
• 就赶紧来医院。 = then come to the hospital right away

So this is a very useful structure to learn for giving advice, warnings, or instructions based on a condition.