De förväntade sig att simhallen skulle vara full, men den var nästan tom när vi kom dit.

Because förvänta sig is a reflexive verb in Swedish. It means to expect in the sense of having an expectation.

So you normally say:

• Jag förväntar mig
• Du förväntar dig
• De förväntade sig

The reflexive pronoun changes with the subject:

• mig = myself
• dig = yourself
• sig = himself/herself/themselves

For de, the correct reflexive form is sig.

A very literal way to think of it is: They expected themselves that..., although in natural English we just say They expected that...

Förväntade sig is the past tense of förvänta sig, meaning expected.

In this sentence:

• De förväntade sig att... = They expected that...

Be careful not to confuse it with:

• vänta = wait
• förvänta sig = expect

Even though they are related historically, they mean different things in modern Swedish.

Here, att introduces a subordinate clause: that.

So:

• De förväntade sig att simhallen skulle vara full
• They expected that the swimming pool would be full

In English, that is often optional:

• They expected the swimming pool would be full
• They expected that the swimming pool would be full

In Swedish, att is very natural here and usually needed.

Skulle vara means would be.

This is used because the sentence describes something that was expected at that time, before they arrived.

So:

• De förväntade sig att simhallen skulle vara full
• literally: They expected that the swimming pool would be full

If you said att simhallen var full, that would sound more like that the swimming pool was full as a fact, not as something anticipated.

So skulle vara expresses an expected situation in relation to a past moment.

Often, yes, but not always in exactly the same way as English would.

In this sentence, skulle is used for a future-from-the-past or expected outcome:

• They expected it would be full

Other common uses of skulle include:

• polite requests: Skulle du kunna hjälpa mig? = Could you help me?
• future in the past: Hon sa att hon skulle komma. = She said she would come

So here, skulle does not mean willingness; it marks what was expected to happen or be true.

Simhallen means the swimming pool or more precisely the indoor public swimming hall / swimming baths.

It is made from:

• sim = swim/swimming
• hall = hall
• simhall = swimming hall
• simhallen = the swimming hall

Swedish often puts the definite article at the end of the noun:

• en simhall = a swimming pool / swimming hall
• simhallen = the swimming pool / swimming hall

So the -en is the definite ending.

Because simhall is a common gender noun, not a neuter noun.

In Swedish, nouns are either:

• en-words (common gender)
• ett-words (neuter)

En simhall is an en-word, so when referring back to it, you use:

• den = it

So:

• simhallen → den

If it were an ett-word, you would use det instead.

Because full agrees with the noun it describes.

Here, it describes simhallen, which is an en-word:

• simhallen skulle vara full

For adjective agreement:

• en-word: full
• ett-word: fullt
• plural/definite forms often: fulla

Examples:

• En sal är full. = A room is full.
• Ett hus är fullt. = A house is full.
• Salarna är fulla. = The rooms are full.

So full is correct because simhall is an en-word.

For the same reason as full: the adjective matches simhallen, which is an en-word.

So:

• den var nästan tom = it was almost empty

Compare:

• En hall är tom.
• Ett rum är tomt.

Because simhallen is an en-word, tom is the correct form.

This is normal Swedish word order for a subordinate clause introduced by när = when:

• när vi kom dit = when we got there / when we arrived there

The order is:

• när
  • subject + verb + place

So:

• när = when
• vi = we
• kom = came
• dit = there

This is straightforward and similar to English.

Dit usually means to there or there with a sense of movement toward a place.

• vi kom dit = we got there / we came there

By contrast, där usually means there in a static sense, location without movement.

Compare:

• Vi åkte dit. = We went there.
• Vi var där. = We were there.

Since kom involves movement toward the place, dit is the natural choice.

Because the whole sentence describes a past situation:

• they expected
• it was
• we came

The timeline is:

1. They had an expectation.
2. We arrived there.
3. At that time, it was almost empty.

So Swedish uses past tense throughout:

• förväntade sig = expected
• skulle vara = would be
• var = was
• kom = came

This keeps the whole sentence anchored in the past.

Yes. Men means but, and it introduces a clear contrast.

First expectation:

• De förväntade sig att simhallen skulle vara full
• They expected the swimming pool to be full

Actual result:

• men den var nästan tom när vi kom dit
• but it was almost empty when we got there

So the sentence contrasts expectation with reality.

Yes. In natural English, the swimming pool is usually the best translation.

But it helps to know that Swedish simhall often refers to a public indoor swimming facility, not just the pool itself.

So depending on context, it could mean:

• the swimming pool
• the swimming baths
• the swimming centre
• the indoor pool

For most learners, the swimming pool is a perfectly good translation here.