Mary didn’t seem to understand why she had to do that.
This may be a slight mistranslation, and on tatoeba it’s noted that the Greek ‘needs a native check’. I think the English would be better as “It seems that Mary doesn’t understand why she needed to do that.” But we need a native speaker . . .
Mary didn’t seem to understand why she had to do that.
I think that if φαίνεται is included in the Greek sentence, then I think it is fair to add the “It seems”. Google translator, though not perfect, gives “it seems, that Mary doesn’t understand why she had to do it.”
I would add that using the English name “Mary” instead of the Greek “η Μαίρη” is also inconsistent