why is metrojn accusative after estas ?
This is called the accusative of measure:
Why wouldn't "longa" be in the accusative as well as "metrojn?" I guess what I'm asking is why can't it be, "La granda aligatoro estas du metrojn longajn."?
I'd say it was because it's in agreement with "granda aligatoro" rather than "du metrojn" like in "La aligatoro estas longa".
"... longas du metrojn" should also be correct but isn't accepted.
Especially since the hint suggests that as the first answer.
Two meters is not really a big alligator, is it? According to Wikipedia their average length is four meters
It is big enough for me.
Tion sxi diris.
in the world of esperanto may be!
It can be big if it is young.
Why isn't longa plural like longaj
Because there's only one alligator. It's the alligator that's long not the meters.
because it's the singular alligator. The meters are not long. The alligator is.
Du metrojn longa aligatoro estas malgranda,