Breakdown of Para el ciervo, cada cuadrado debe ser muy preciso.
ser
to be
muy
very
para
for
la
the (feminine)
Questions & Answers about Para el ciervo, cada cuadrado debe ser muy preciso.
Why is it debe ser and not debe de ser?
Deber followed directly by an infinitive (like ser) expresses a strict obligation or necessity, meaning "must" or "has to." If you used debe de ser, the meaning changes to probability or a strong guess, which would mean "each square is probably very precise."
Why do we use Para at the beginning of the sentence instead of Por?
Why does the sentence use ser instead of estar for being precise?
Why doesn't cada change to match the masculine noun cuadrado?
The word cada (meaning "each" or "every") is an invariable adjective. It never changes to match gender or number, so it stays exactly the same whether it modifies a masculine word like cuadrado or a feminine word like vez.