"It is a fork."
Translation:Det er en gaffel.
"den" can be used whenever the noun it's referring to is masculine or feminine, whereas "det" is namely for neuter nouns. However, det can also be used when referring to masculine and feminine nouns, as is shown in the sentence above (Det er en gaffel). The only instance when "det" can't be used with masculine or feminine nouns is when it means "that," going directly in front of the noun (for instance, det barnet meaning that child). But, that is something you will learn later in the course. :D
I can't say for certain whether that translation is actually incorrect, as I'm not a native speaker of Norwegian, but I can say that "den" is usually used when a masculine and/or feminine noun has already been mentioned. Typically if the noun hasn't been mentioned previously, "det" is used instead. Here's an example:
- "Er det din gaffel?" = Is it your fork? (You could also say "Er dette din gaffel?" for "Is this your fork?")
- "Ja, den er min." = Yes, it is mine.
Here's a similar example:
- "Det er min gaffel, ikke din." = It is my fork, not yours.
- "Nei, den er min!" = No, it's mine!
You could also say something like: Det er en kopp, så den inneholder væske. = It is a cup, so it contains liquid.