"The color of the elephant is gray."
Translation:Το χρώμα του ελέφαντα είναι γκρι.
Because the nouns belong to different declensions.
Which is another way of saying that they inflect differently (they take different endings).
το παιδί inflects like other neuter nouns in -ι (το αγόρι, του αγοριοόυ - το κορίτσι, του κοριτισού - ...)
ο ελέφαντας inflects like other masculine nouns in -ας (ο πατέρας, του πατέρα - ο μάγειρας, του μάγειρα - ...).
But neither inflects like the other, because the words belong to different groups.
According to the analysis that the computer program that grades the sentences shows you used two letters from the wrong keyboard.
"το χρώμα τou ελέφαντα είναι γκρι"
Look carefully at the word using the Greek keyboard on top and the second one using the English keyboard.
του this is the Greek keyboard word.
τou this is the English keyboard here the letters ou are shorter and there is a tail on u.
I'm afraid that the way the algorithm is programmed only Greek letters can be accepted for Greek words.
To help you find where the letters are on the Greek keyboard see these links. https://forum.duolingo.com/comment/23430853
Sorry, I should have asked you what kind of a Greek keyboard you were using. If it is the kind where you type the letters then copy-paste them into the text then it might be the reason the wrong letters were shown.
You should access the Greek keyboard on your computer. It's easy to switch for the English to and back from the Greek.
Just see the link I gave above to get the keyboard.
Impossible to say without seeing what you saw (a URL to a screenshot that you have uploaded to a website somewhere would be helpful), but common causes are:
- you had a translation exercise rather than a "type what you hear" exercise or vice versa, and you copied the wrong sentence
- the system showed you two or three possible translations and you copied all of them together into one answer
- you re-typed (rather than copy and paste) the answer and made a mistake
Did you report your sentence as "my translation should be accepted"?
If so, I'm guessing that this is what you typed:
το χρώμα τou ελέφαντα είναι γκρι
(There is a report for that sentence to be accepted which comes from around the same time as your comment.)
That answer mis-spells the third word, by using the English letters "o" and "u" rather than the Greek letters ο υ