"The compass lets us know where our grandmother is."
Translation:Cái la bàn cho chúng tôi biết bà của chúng tôi đang ở đâu.
And we're just supposed to guess the word order here? Why doesn't ở đau at the end of the sentence ask the question Does the compass let us know where our grandmother is? Wouldn't it be really, really nice if these things were actually taught rather than just tossed at us like this?
"Does the compass let us know where our grandmother is?" is a yes/no question, so it would be formulated with "có ... không?" or one of the similar constructions. Also in Vietnamese the sentence structure is pretty much always subject-verb-object, which is not changed when constructing questions. In this case the subject of the sub-clause is "our grandmother" (bà chúng tôi), the verb is "is" (ở) and the object is "where" (đâu), so the sentence in Vietnamese is "bà (của) chúng tôi (đang) ở đâu". I'm sorry but I also have to point out that these things were actually taught in previous lessons. Although I understand the frustration that the many errors and inconsistencies in this course can create, sometimes taking a moment to reflect can make us realise that we too can make errors and wrong assumptions.