The Swedish sentence means both "They are opening ..." and "They open ..." I would say that if you are translating it into English, it will depend on the context: "they open the windows" means "they usually open the windows", whereas "they are opening the windows" will mean that they are performing that action right now. I hope this comment helps!
Thank you! It is a hard thing for me to get used to. I was just hoping there was something to indicate that I was missing, lol. Being used to English, I want to know WITHOUT context, whether the person means "right now" or "on a regular basis." I would imagine people have to ask. For example, I'm on the phone with my friend. She says her daughter reads a book in her bedroom. I might have to ask, "You mean, right now? Or in general?" Otherwise, I don't know whether we can discuss her surprise birthday party or not. I'm guessing that people would add things like "in the evenings" or "brukar" or "just nu" to make it clear. (It seems I'm just thinking out loud here, asking and answering my own questions, lol! But maybe you can agree or disagree and that would be helpful to me!)
I agree with you! Being a native Spanish speaker, it was hard at first to accept this peculiarity of the Swedish language, lol. "They are opening" would be "Están abriendo" and "They open" would translate as "Abren". Plus, in Spanish, "they" would also indicate if the noun was a feminine plural ("Ellas abren") or a masculine plural ("Ellos abren"). So, as you can see, even the ENGLISH "more accurate without a context" sentence would still be a mystery to a Spanish speaker (i.e. are "they" women or men?). That being said, I find that as I progress in this wonderful course, I am slowly starting to "think in Swedish" and getting used to express the idea and not be looking for an exact correspondence with my Spanish (or English) equivalents. One day at a time, of course! Best regards :)
Because "öppna" is the base form of the verb ("to open") and "öppnar" is the present participle form of the verb ("open" or if the subject was singular it would be "opens").
In this sentence, "öppnar" is the only verb, so it take the present participle form.
You could use "öppna" in a sentence where there is another verb, such as: "De hatar att öppna fönstret." (They hate to open the window.) "Hatar" takes the present participle form and the other verb, "öppna," takes the base form.
If you said, "De öppna fönstret" in Swedish, that would be like saying in English, "They to open the window." Not good.