"It seems that they see better with their new glasses."
Translation:Il semble qu'elles voient mieux avec leurs nouvelles lunettes.
The exercise accepts (for months) answers with ils and elles. So the most likely reason was that your answer contained a mistake (a typo for instance, so that you may not have seen). Of course, your choice of ils was not the mistake in your answer.
If Duo grades your answer as wrong then Duo's algorithm pick one possible answer among all the defined ones.
This answer may or may not fit your choice between ils and elles.
If the answer shown to you is with elles but you answered with ils, it doesn't imply that your choice of ils was the reason why your answer was graded wrong in the first place.
Il paraît, il semble and on dirait have all the same meaning and should be accepted, I think.
I had to translate the written English sentence. Why "ils voient" is not accepted is beyond my understanding. With no context I must assume it is masculine, yet it is marked wrong
I said "Il a l'air qu'ils voient mieux avec leurs nouvelles lunettes" and was marked wrong. When can you use "l'air"?
Pourquoi pas: "Il semble qu' ils voient mieux avec leurs lunettes nouvelles"?
Because nouvelles is one of the few adjectives that comes before the noun
I was marked incorrect for il parait (avec circonflex!) instead of il semble.
Il paraît will be used to refer to a rumor, something you heard but are not sure of.
Il semble is more used for something that you could witness or something you heard from a more certain source.