Learn Swedish: Det blåser mycket. Därför kan vi inte segla. - It is very windy. Therefore we cannot sail.

In Swedish, the verb must almost always be the second idea in a main clause (this is called the V2 rule). Because the sentence starts with the connector därför (therefore) in the first position, the verb kan must come immediately after it. The subject vi gets pushed to the third position.

Why does the first sentence say det blåser instead of using a word for "windy"?

In Swedish, weather is often described using verbs rather than adjectives. Instead of saying "it is windy", Swedes say det blåser (literally "it blows"). You have probably seen this with other weather words too, like det regnar (it rains) and det snöar (it snows).

Why is inte placed after vi rather than before it?

In a main clause, the negation word inte usually comes after both the verb and the subject. Since därför forced the verb kan and the subject vi into the second and third spots, inte just falls in line right after them.

Is mycket an adjective or an adverb here?

Here, mycket acts as an adverb describing how much the wind is blowing. While in English we might say "it is very windy" (using an adjective), Swedish says "it blows a lot" (det blåser mycket).