Learn Swedish: Nu tar vi bussen. - Now we take the bus.

This is because of the V2 (verb-second) rule in Swedish. The verb must usually be in the second position of a sentence. Because we start with the time adverb Nu in position one, the verb tar must come right after it. This pushes the subject vi into position three.

Can this sentence also mean 'Now we are taking the bus'?

Yes! Swedish does not have a separate continuous tense like the English '-ing' form. The present tense verb tar translates to both 'take' and 'are taking' depending on the context.

Why is the word for 'the bus' written as bussen?

In Swedish, the word for 'the' attaches to the end of the noun instead of being a separate word. Because buss is an en word, we add -en to the end to make bussen.