jīntiān zǎoshang wàimiàn xiàxuě le, wǒ méi dài sǎn, zhǐhǎo zài gōngsī ménkǒu děng le yíhuìr.

In Mandarin, time expressions very often come near the beginning. A very common neutral word order is:

Time + place + verb/action

So here:

今天早上 外面 下雪了
= This morning, outside, it snowed / it was snowing

You can move things around for emphasis, but 今天早上 at the front is the most natural everyday order.

外面 means outside or outdoors. It tells you where the snow was happening from the speaker's point of view.

Without it, 今天早上下雪了 is still a perfectly good sentence. Adding 外面 makes the scene a little more vivid, almost like:

This morning, outside, it was snowing.

So it is not strictly required, but it sounds natural and informative.

Yes, basically. 下 means to fall, and Mandarin uses it with weather expressions like:

• 下雨 = to rain
• 下雪 = to snow

So 下雪 is the normal verb for to snow.

Also, unlike English, Mandarin does not need a dummy subject like it. English says It’s snowing, but Mandarin simply says 下雪.

In 外面下雪了, the 了 does not just mean simple past tense. It often marks a new situation or change of state.

So 下雪了 often means something like:

• It started snowing
• It has become snowy
• It was snowing (as a new/relevant situation)

That fits the sentence well, because the snow created the problem that follows: the speaker had no umbrella.

For a past action or something that did not happen, Mandarin usually uses 没 or 没有, not 不.

So:

• 没带伞 = didn’t bring an umbrella
• 不带伞 = don’t bring umbrellas / won’t bring an umbrella / am not bringing an umbrella depending on context

Here the speaker is talking about what happened earlier today, so 没带伞 is the right choice.

带 means to bring along / have with you. It focuses on taking something with you as part of your trip or situation.

So 带伞 means:

to bring an umbrella along

拿 means to take / hold / pick up and is often more physical or immediate.

Compare:

• 我没带伞。 = I didn’t bring an umbrella with me.
• 我去拿伞。 = I’m going to get the umbrella.

In this sentence, 带 is the natural verb.

Because classifiers are not required with a bare noun object.

Mandarin needs a classifier when you use a number or a demonstrative, for example:

• 一把伞 = one umbrella
• 那把伞 = that umbrella

But when you are just talking about the thing in general as the object of a verb, you can simply say:

带伞

So 没带伞 is completely normal.

只好 means to have no choice but to.

It shows that the speaker did not really want this option, but the situation forced it. In this sentence:

只好在公司门口等了 一会儿
= I had no choice but to wait at the company entrance for a while

So 只好 adds the idea of inconvenience or helplessness.

In Mandarin, location phrases with 在 usually come before the verb.

So:

在公司门口等
= wait at the company entrance

This is normal Mandarin word order:

• 我在家吃饭。 = I eat at home.
• 他在学校学习。 = He studies at school.

Here, 公司门口 means the entrance to the company / outside the company door / by the company entrance.

This 了 is different from the earlier one.

In 等了一会儿, the 了 marks the verb 等 as a completed event: the speaker waited for some amount of time.

So:

• 下雪了 = change of situation / new state
• 等了一会儿 = completed action with duration

This is a very common pattern:

verb + 了 + duration

For example:

• 看了一小时 = watched for an hour
• 睡了十分钟 = slept for ten minutes
• 等了一会儿 = waited for a little while

Here 一会儿 means a little while or for a short time.

So 等了一会儿 means:

• waited for a bit
• waited for a little while

The exact length is vague. It is intentionally not precise.

This is because of tone change.

Normally 一 is first tone: yī. But before a fourth-tone syllable, it usually changes to second tone. Since 会 is fourth tone (huì), 一会儿 is pronounced:

yíhuìr

Also, the 儿 here is an -r ending, often called erhua. In speech, 会儿 is often pronounced like huìr, not as two fully separate syllables.

Yes. Mandarin often omits the object when it is obvious, unknown, or unimportant.

So 等了 一会儿 simply means waited for a while. The sentence does not say exactly what the speaker was waiting for:

• maybe waiting for the snow to ease up
• maybe waiting for someone
• maybe waiting before going outside

Chinese is often comfortable leaving that unsaid if the situation already makes sense.