Breakdown of O que está nesta caixa?
o que
what
estar
to be (temporary / location)
neste
in this (m/sg), nesta (f/sg), nestes (m/pl), nestas (f/pl)
a caixa
the box
Questions & Answers about O que está nesta caixa?
How do we get the word nesta?
Nesta is a contraction of the preposition em (in/on/at) and the feminine singular demonstrative pronoun esta (this). Because caixa (box) is a feminine word, we use esta, and since we are talking about what is in the box, they combine: em + esta = nesta.
Why use está for 'is' instead of é?
Why is there an o before que?
Does esta mean 'this' or 'that'?
Esta means 'this', referring to something close to the speaker. If the box were further away, you would use essa ('that'), and the contraction would become nessa (em + essa).