Learn Hardcore Chinese: wǒ zài bàngōngshì děng lǎobǎn děng le yí gè xiǎoshí le. - I’ve been waiting for the boss in the office for an hour.

我在办公室等老板一个小时了 (without the second 等 and without 了 immediately after 等) is unnatural, because the usual duration pattern is 等了 + Duration, not 等 + Duration when you want to emphasize how long.

The V + O + V + 了 + Duration pattern is especially common when the object is specific (like 老板, “the boss”).

What is the difference between the two 了 in 等了一个小时了? Can I drop one of them?

The two 了 have different functions.

The first 了 (right after 等) is verb-了, marking a completed stretch of the action:
- 等了一个小时 = “waited for an hour” (this amount of waiting has been completed)
The final 了 (at the very end of the sentence) is sentence-了, often called “change-of-state 了”. It shows that the situation has reached a new state now:
- …一个小时了 = “it’s now been an hour (already)”

So the full sentence implies:

I have (already) spent an hour waiting, and this is the situation at this moment (I’m probably still waiting).

About omitting them:

If you remove the final 了:
我在办公室等老板等了一个小时。
→ Grammatically fine. It can sound more like you are just reporting a past fact (you may or may not still be waiting).
If you remove the verb-了 but keep the final 了:
我在办公室等老板一个小时了。
→ This is unnatural; the duration construction normally needs V + 了 + Duration.

So:

First 了 = part of “waited for an hour”
Final 了 = “by now / already / up to this point”

Does this sentence mean I am still waiting now, or that I already finished waiting?

With 等了一个小时了, the default reading is:

You have already waited an hour and are still in that state now (i.e. you are still waiting).

If you want to emphasize that you already finished waiting, you could say something like:

我在办公室等老板等了一个小时，就走了。
I waited for the boss in the office for an hour, then left.

Or more clearly finished:

我在办公室等老板等了一个小时，后来见到他了。
I waited for the boss in the office for an hour, and then saw him.

So:

…一个小时了 usually implies “it has been (and still is) an hour”.
Past + finished is usually made clear by additional context.

What exactly is 在 doing here? Is it a location marker or a progressive marker (like “am waiting”)?

In 我在办公室等老板等了一个小时了, this 在 is:

a preposition indicating location: 在办公室 = “at/in the office”.

Chinese has another 在 used before the verb to mark the progressive aspect:

我在等老板。 = “I am waiting for the boss.”

But in your sentence, the first 在 is attached to 办公室, not to 等:

我在办公室等老板…
“I, at the office, wait for the boss…”

If you want to make the progressive meaning explicit as well, you can say:

我正在办公室等老板。
我在办公室正在等老板。

Here 正在 (or 在 before the verb) is the progressive marker. In the original sentence, the ongoing feel mainly comes from the combination of 等了一个小时了 rather than from 在.

Why is it 一个小时 instead of just 一小时? Is 个 required?

Both are possible:

一个小时
一小时

Differences:

一个小时 is more colloquial and very common in speech.
一小时 sounds a bit more formal / written.

So:

Everyday speech: 等了一个小时了 is most natural.
In written, formal style: 等了一小时 is common.

You cannot drop the measure word completely (一小时 is actually “one hour”, just with the measure word 小时 itself). The “extra” 个 is a very general classifier often inserted in speech before time nouns like:

一个星期
一个月
一个小时

How should I pronounce 一个小时 and why is 一 pronounced yí here?

Pronunciation:

一个小时 → yí ge xiǎoshí

Two points:

Tone sandhi for 一
- 一 is normally yī (1st tone).
- Before a fourth-tone syllable, it changes to yí (2nd tone).
- 个 is 4th tone in isolation (gè), so 一 + 个 → yí gè (often yí ge in fast speech).
Neutral tone for 个 in this phrase
- In everyday speech, 个 in 一个 is usually read with a neutral tone, so you’ll hear yí ge, not a full 4th tone.

So overall: yí ge xiǎo shí.

What is the difference between 小时 and 钟头? Could I say 一个钟头 instead?

Yes, you can say:

我在办公室等老板等了一个钟头了。

Differences:

小时:
- Standard, neutral, used everywhere (spoken and written).
钟头:
- More colloquial, slightly more casual, common in speech and in some dialect areas (e.g. Northern Mandarin).

Meaning-wise, they are the same: one hour.

Could I say 我在办公室等了老板一个小时 instead? Is that correct, and does it mean the same?

Yes, 我在办公室等了老板一个小时 is grammatically correct and natural.

Comparison:

我在办公室等老板等了一个小时了。
- Uses V + O + V + 了 + Duration + 了.
- Feels a bit more emphatic about the ongoing situation.
- Final 了 implies “it’s now been an hour (and I’m still in that situation)”.
我在办公室等了老板一个小时。
- Uses 等了 + Object + Duration.
- A straightforward report: “I waited for the boss for an hour.”
- Without final 了, it doesn’t explicitly say whether you’re still waiting; context decides.

If you want the “still now” feeling with the second pattern, you can also add a final 了:

我在办公室等了老板一个小时了。
(Also acceptable; speech habits vary by region. Some speakers slightly prefer the repeated-verb version with a specific object.)

Why is the object 老板 placed before the duration, instead of after, like in English “waited for an hour for the boss”?

Basic order in Chinese is:

Subject + (Time/Place) + Verb + Object + (Duration / other complements)

So we get:

我在办公室等老板等了一个小时了。
我在办公室等了老板一个小时。

Putting the duration before the object, like:

✗ 我在办公室等了一个小时老板。

is unnatural. The object normally comes directly after the verb (or right after V + 了), and the duration follows them.

So:

等 + 老板 + 等了 + 一个小时
等了 + 老板 + 一个小时

are the natural word orders.

Do I have to include 老板? What happens if I say 我在办公室等了一个小时了?

You can omit 老板 if it is clear from context who you are waiting for. Then you’d say:

我在办公室等了一个小时了。
I’ve been waiting in the office for an hour.

Differences:

With 老板:
- You explicitly say who you are waiting for.
Without 老板:
- You just stress the fact you’ve been waiting for an hour; the listener must infer from context.

Grammatically, both are fine.

If I just say 我在办公室等老板, without the 等了一个小时了, how does the meaning change?

我在办公室等老板。
→ “I am waiting for the boss in the office.” (a simple statement of the action)

No information about:

how long you have been waiting,
whether it’s already been a significant amount of time.

When you add 等了一个小时了, you:

specify the duration (an hour),
usually express a sense of “already this long by now”, which can carry impatience or complaint in context.

So:

等老板 = just the action.
等老板等了一个小时了 = action + specific duration + “up to now” nuance.