I had to take the duoLingo "Determiners/1" test about 42 times to get it right; there seems to be no rhyme or reason to it.
Some examples of where I stubbed my toe:
0)"Quien bebe de esta taza?"
I tried: Quien bebe de este taza? Correct answer is: Quien bebe de esta taza?
Is it "esta" instead of "este" because "taza" is feminine, I wondered? But that doesn't seem to be the case, because for this:
1) "Es[e,o] vaso es grande I tried: "Eso" but the correct answer is: "Ese"
2) "Esos pajaros no son negros" I tried: "These birds are not black" Correct answer is: "Those birds are not black"
I finally got through the test primiarily from memorization.
Is this (or that) the actual Montezuma's revenge?