Why use we "det" and not "den" ?
I thought , "en restaurang" -> then I use "den".
Now I know that I must to use "det".. But I am not sure why.
When "det" is used, the gender has not been defined. Therefore we use "det". After we know what "det" or "it" is, then we use the proper det/den as long as we are still referring to the same thing.
i.e. Det är en restaurang. Den är ....
That is one of the coolest things have ever learned about any language. Not quite sure why it blows my mind so much, but thank you!
I guessed "That is a restaurant" and it was marked correct. Does "det" pull double duty as "that" and "it"?
Yes, the "t" in "det" in normally silent, but "ng" in "restaurang" is pronounced [ŋ] like "ng" in sing for example.
Yes, it's very common to either drop an ending t entirely or to some extent restrict its pronunciation. It varies a lot by word, sociolect, etc., so it's impossible to give a list.
Just a couple questions ago I thought "det" was pronounced "dom", but here it's seemingly pronounced "dey"?
The words de and dem are both pronounced as though they were written /dom/, but det is pronounced as though it were written /de/. (or /det/ if we speak really slowly and clearly).