I think they're a bit more lenient with exercises where you're not listening and typing out what you hear but in this case you have to type out what is said exactly.
Contraction. I am vs I'm. Remember that particular English writing teacher? I think its a similar thing here based on other reaponses on here to this subject, and my experience with native speakers.
Duoliingo teaching you a language wants us yo learn the standard way initially, im assuming. It's kay though! As we become fluent we will know when we need to or not use contracted versions of a sentence
The difference between 'I do not' and 'I don't' or
'We will not' vs 'We won't'
In both examples we save words and energy. Its about the way its spoken, and the subtle meanings. Contractions
Like when you insist on something:
"I will be the best at DuoLingo!" vs "I'm gonna/I'll be the best ay DuoLingo"
The first one can be more formal, yet more powerful and clear because you spelled it out and thus showed intention. Where as the second is quicker, less formal, but not as serious and casual and can be seen as more freindly even.
It ultimately depends on the context, but hopefully this clears it up a bit.
Look at the the ending of the word for example the girl in spanish would be la chica and the la come from the end of the word chica now for boys the ending may not be exactly the same sometime for boys it would end in an o so it would be el chico and for la fruta it end with an a and the door is la puerta it ends in an a so all i can say is that if it starts with la the ending of the word to the right of it ends in an a and if it doesnt end an a use el
I was given the option between los parablas and los periodicos (I know I'm missing the accented letters) in the sentence "Yo leo los ___". I chose periodicos, last I remember meaning periodicals, i.e. newspapers...idk how choosing "i read the newspapers" over "i read the words" is incorrect.