qǐng jiǎnchá guāngmāo de zhǐshìdēng.

Here 请 is a polite request marker, similar to please in English.

So 请检查光猫的指示灯 is a polite way to say Please check the optical modem’s indicator light(s).

A useful extra point: 请 can also mean to invite or to ask someone to do something, depending on context. In this sentence, it is clearly the polite please usage.

In Mandarin, the subject is often omitted when it is obvious from context.

In a request or instruction like this, the listener is understood automatically, so 你 or 您 does not need to be said.

So:

• 请检查光猫的指示灯。 = Please check the optical modem’s indicator light(s).
• 请你检查光猫的指示灯。 = Please check the optical modem’s indicator light(s).

Both are grammatical, but the version without the subject is very natural.

It is basically a polite imperative.

Mandarin often uses 请 + verb for instructions, requests, announcements, and customer-service language. It is more polite than a bare command, but it is still direct and practical.

So this kind of sentence is very common in:

• tech support
• written instructions
• service conversations
• formal notices

It sounds natural and standard, not rude.

Here 的 links a modifier to a noun. In this sentence, it marks a relationship similar to ’s or of in English.

So:

• 光猫 = optical modem / fiber modem
• 指示灯 = indicator light
• 光猫的指示灯 = the optical modem’s indicator light(s)

A good way to think of it is:

A 的 B = B of A or A’s B

So 光猫的指示灯 literally means the indicator light(s) of the optical modem.

光猫 is a common everyday Chinese term for a fiber optic modem or optical network terminal.

It is especially common in internet-service and home-network contexts in China.

Literally, the characters mean:

• 光 = light, optical
• 猫 = cat

But you should not interpret it literally as light cat. It is a technical colloquial term.

A helpful cultural note: 猫 here is used because it sounds like the second part of modem in casual Chinese usage. So 猫 became a common shorthand for modem-related devices.

This is one of those vocabulary items that makes more sense historically than literally.

In informal Chinese tech language, 猫 came to be used because it echoes the sound of modem. Over time, this became a standard colloquial shorthand.

So you may see:

• 猫 in older or casual internet/device talk
• 光猫 for a fiber modem / optical modem

Even though the character means cat, in this expression native speakers do not picture an animal. They just recognize it as part of a device name.

检查 means to inspect, examine, or check. It suggests a deliberate checking action, not just looking casually.

Compare:

• 看 = to look at, to see
• 查看 = to check, to look over
• 检查 = to inspect, to examine carefully

In a tech-support sentence, 检查 is a very natural choice because the speaker wants the listener to verify the status of something, not merely glance at it.

So 请检查光猫的指示灯 sounds more precise and task-oriented than using 看.

Yes, absolutely. That sounds very natural.

Adding 一下 often softens the tone and makes the request sound a bit more conversational or less abrupt.

Compare:

• 请检查光猫的指示灯。 = Please check the indicator light(s) on the optical modem.
• 请检查一下光猫的指示灯。 = Please check the indicator light(s) on the optical modem for a moment / please just check them.

In English, 一下 often does not need a separate translation. Its main effect is on tone, making the request smoother.

It can depend on context. In Chinese, nouns often do not have to show singular or plural explicitly.

So 指示灯 can mean:

• the indicator light
• the indicator lights

If the context is a modem, a speaker may really mean the set of status lights in general, even though Chinese does not mark that clearly in the noun itself.

If you want to be more specific, you can say:

• 一个指示灯 = one indicator light
• 几个指示灯 = several indicator lights
• 电源指示灯 = the power indicator light

So the original sentence leaves the number open and relies on context.

In citation form, it is:

• 请 = qǐng, third tone
• 检 = jiǎn, third tone
• 查 = chá, second tone

So the dictionary tones are qǐng jiǎn chá.

But in natural connected speech, when one third-tone syllable comes before another third-tone syllable, the first one usually changes in pronunciation to something like a second tone. This is called third-tone sandhi.

So 请检查 is often pronounced more like:

• qíng jiǎnchá

But it is still written qǐng jiǎnchá in pinyin.

Here 的 is pronounced de with a neutral tone.

So:

• 光猫的指示灯 = guāngmāo de zhǐshìdēng

It is not pronounced as a full stressed dì or dí in this sentence.

This unstressed neutral-tone de is extremely common when 的 links modifiers to nouns.

Mandarin does not use articles the way English does.

So where English needs words like:

• a
• an
• the

Chinese usually just uses the noun directly and lets context show whether it is definite or indefinite.

That is why 光猫的指示灯 can naturally mean:

• the optical modem’s indicator light
• the optical modem’s indicator lights

without any separate word for the.

This is completely normal in Mandarin and is one of the big structural differences from English.