Hvis græsplænen er våd om morgenen, bliver vi ikke derude så længe.

Hvis introduces a condition, just like if in English. It starts a subordinate clause: Hvis græsplænen er våd om morgenen.

That clause sets up the situation under which the main clause is true.

Græsplæne means lawn in the indefinite form.
Græsplænen is the definite form, meaning the lawn.

For many Danish nouns, definiteness is added as an ending instead of with a separate word like the. So:

• en græsplæne = a lawn
• græsplænen = the lawn

Because græsplæne already ends in -e, the definite ending appears as -n here.

Because græsplænen is a common gender singular noun.

In Danish, predicative adjectives often agree like this:

• common gender singular: våd
• neuter singular: vådt
• plural: våde

So:

• græsplænen er våd
• gulvet er vådt
• skoene er våde

Even though græsplænen is definite, it is still singular common gender, so våd is correct.

Om morgenen is the normal Danish way to say in the morning or in the mornings, depending on context.

This is a common time expression:

• om morgenen = in the morning
• om aftenen = in the evening
• om natten = at night

Be careful not to confuse it with:

• i morgen = tomorrow
• i morges = this morning

So om morgenen is about the time of day, not about tomorrow.

This is because Danish main clauses normally follow the V2 rule: the finite verb comes in the second position.

When the sentence begins with a subordinate clause like Hvis græsplænen er våd om morgenen, that whole clause counts as the first element. So in the main clause, the verb must come next:

• Hvis græsplænen er våd om morgenen, bliver vi ikke derude så længe.

If you started directly with the subject, you would say:

• Vi bliver ikke derude så længe, hvis græsplænen er våd om morgenen.

So both patterns are possible, but when the hvis-clause comes first, inversion happens.

In a normal Danish main clause, ikke usually comes after the finite verb and after the subject if inversion has happened.

Here the order is:

• bliver = finite verb
• vi = subject
• ikke = negation

So:

• bliver vi ikke ...

Compare:

• Vi bliver ikke derude så længe.
• Hvis ..., bliver vi ikke derude så længe.

A useful contrast is that in subordinate clauses, ikke usually comes before the finite verb:

• hvis græsplænen ikke er våd

So the position of ikke is different in main clauses and subordinate clauses.

Not here. In this sentence, bliver comes from blive, but blive can mean several things depending on context.

Common meanings include:

• become
• remain
• stay

In a sentence about being somewhere, blive very often means stay or remain:

• Vi bliver hjemme. = We stay home.
• Bliver du her? = Are you staying here?

So here bliver vi ... derude means we stay out there.

Derude means something like out there or outside there, pointing to a place away from the speaker.

• ude = outside / out
• derude = out there

In many contexts, English may translate both simply as outside, but Danish derude adds a sense of location or distance.

So vi bliver ikke derude suggests we won’t stay out there.

Here så længe means that long or for so long.

With the negation ikke, the phrase ikke ... så længe means:

• not that long
• not for very long

So it expresses duration.

Be careful: så længe can mean different things in other contexts. For example:

• så længe du vil = as long as you want

But in this sentence, it is about length of time.

Not always. You can also say ikke længe, and that is very natural.

Compare:

• Vi bliver ikke derude længe.
• Vi bliver ikke derude så længe.

Both are correct. The version with så can sound a bit more like not that long or can connect more clearly to an implied comparison or expectation.

So så is not strictly required, but it adds a nuance.

That is the normal neutral order for these adverbials in Danish: place often comes before duration/time.

So:

• derude = place
• så længe = duration

This gives the natural sequence:

• vi bliver ikke derude så længe

Different word orders are sometimes possible for emphasis, but this order is the most standard here.

Because the sentence begins with a subordinate hvis-clause, and the comma marks the boundary before the main clause begins.

So:

• Hvis græsplænen er våd om morgenen, = subordinate clause
• bliver vi ikke derude så længe. = main clause

This comma is standard in Danish when a subordinate clause comes first.