"The green strawberry."
Translation:Det grønne jordbær.
When there is a definite article in the form of "The [adjective] [noun]" in English, Danish has the form of "[Det/Den] [adjective in e-form] [noun]". This also happens with possessive pronouns and nouns in genitive form. For example:
"En grøn bil" = A green car
"Den grønne bil" = The green car
"Min/Din/Jeres/Vores/Karolines grønne bil" = "My/Your (singular)/Your (plural)/Our/Karoline's green car" (this is also true with all possessive pronouns, it was just starting to look a bit messy)
However, in other constructions:
"Bilen er grøn" = The car is green
"Mit jordbær er grønt" = My strawberry is green
Sorry, but i don't understand. Why is it not "det groent jordbaer", even Duolingo itself at the beginning of the lesson said, that definite nouns with an adjective in front, get a "det/den" and an adjective, which is either ending in -t or in - depending on whether or not it is neuter.
From the Tips Notes section for this skill:
Adjectives and Definite Nouns
While nouns normally express definiteness using a postfix, this changes to using an article if any adjectives (such as a color) is attached to the noun.
If the color (or in general adjective) is used with a definite noun, then it is put between the definite article and the noun: En rød bil (a red car) becomes den røde bil (the red car). In this case the adjective is declined the same way as for the plural, no matter the grammatical number or gender of the noun.
As a reminder, the car without any adjectives is simply bilen, expressing the definite with the -en postfix and no article involved.