Brazilian Portuguese Grammar

Example	Note		Is the combination possible? If so, crasis is mandatory.
			Yes	No
Fui à escola	Fui (verb ir) is followed by preposition a	The noun escola is feminine: a escola	Yes
I went to school
Fui ao museu.	Fui (verb ir) is followed by preposition a	The noun museu is masculine: o museu		No
Eu acordei às 6 da manhã.	Always use às (at) before clock times. *The preposition used is a + hora* (hour), which is a feminine noun.**		Yes
I woke up at 6 in the morning.
Você perguntou àquele homem?	Verb perguntar (to ask) requires preposition a	Pronoun aquele is always a good candidate for crase	Yes
Did you ask that man?
Você conhece aquela mulher?	Verb conhecer (to know somebody) is not a prepositional verb: it doesn't require a preposition.	*The noun mulher* (woman) is a feminine noun.**		No
Do you know that woman?

The grave accent is optional when the noun which follows preposition a is a feminine proper name or a feminine possessive pronoun (which may take the feminine articles):

Contei a história a sua irmã

Contei a história à sua irmã

Contei a história a Maria

Contei a história à Maria

I told your sister the story - contar algo a alguém (tell something to somebody/ tell somebody something): verb contar is a prepositional verb, followed by preposition a.

The grave accent is also required in adverbial phrases such as às vezes, à direita, prepositional phrases such as contrário à and conjunctive phrases such as à medida que.

The grave accent is not used in adverbial phrases that have repeated terms such as frente a frente and passo a passo.

Adverbials of manner and instrument also take the grave accent as long as the noun is feminine, e.g.:

escrever à caneta (write in pen).

pagar à vista (pay in cash)

but

pagar a prazo (pay in installments)

prazo => masculine word