"The knife is in the boot."
Translation:Il coltello è nello stivale.
Outside the US and Caribbean, this is actually a useful phrase. Imagine you are in a car ready to eat food that you need to cut up, and your passenger says "the knife is in the boot". I've probably said it myself on several occasions.
You get out and retrieve the knife, because EN "boot" = US "trunk".
So Duo should accept the translation to "... nel portabagagli". I haven't tried, but I doubt this.
It's lo stivale(the noun starts with s+consonant) there fore its nello "lo" is every masculine noun starting with z or s+consonant and i think ch is as well "l' " is for nouns that start with a vowel and "il" is every other masculine noun(in singular of course) in order when combining them with in they would be nello, nell' and nel. Hope it helps and that it isnt too wrong... :)
https://en.wikipedia.org/wiki/Italian_grammar#Articles is the most complete list that I've found of forms that need "lo".
Note that "ch..." is not one of them, except for foreign imports like "lo chef". Indeed, some foreign imports may be missing from the list - can you find all 5 non-Italian letters of the English alphabet?
If you actually typed the è (e-grave) character then something else must have been wrong. Two characters e-apostrophe, as I see in your post, aren't recognised; they are a kludge used by people who can't type è.
Alternatives: 1. Select è in Duo's character list. 2. Just type e unaccented; Duo warns but does not reject. 3. On a computer keyboard, hold down the Alt key, type 0232 and let go. 4. On a smartphone, tap and hold on the e; a menu of all accented variants should appear; drag to the one you want and let go.
Don't want to repeat so see my reply to RoDiazG above. Google is right for everyone except US English speakers. Duolingo is a US website.
There seem to be several Italian words for the same thing: bagagliaio, portabagagli, vano bagagli, e baule (French pronunciation?). C'è un italiano gentile che possa spiegarci?