Questions & Answers about Vi har stängt butiken tidigt idag.
Why does the verb stänga (to close) become stängt here instead of ending in -at?
Stänga is a Group 2 verb. To make the supinum form (the verb form used after har), Group 2 verbs drop their final -a and add a -t. That is why it becomes stängt. Group 1 verbs are the ones that take the -at ending.
How do we know to use har stängt (have closed) instead of the simple past tense stängde (closed)?
We use har plus the supinum because the action has a direct connection to the present. By saying Vi har stängt, you are emphasizing the current result: the shop is closed right now. If you were just narrating what happened at a specific time in the past, you would use the past tense stängde.
Why is there a -t at the end of tidigt (early)?
Is it okay to write idag as two words (i dag)?
Yes, both idag and i dag are perfectly correct and mean exactly the same thing. Writing it as a single word is very common in modern, everyday Swedish.