Learn Portuguese Grammar with this is amazing app and improve your Portuguese Grammar.
Completely OFFLINE

Common Grammars
+ Verbs
+ Pronouns
+ Sentence
+ Subjunctive
+ Adverbs
+ Prepositions
+ Coordinate conjunction
+ Subordinate conjunction
+ Tenses
+ Compound Tense
+ Interjection
+ Intonation
+ Nouns
+ Indefinite article
+ Conjugation
+ Conjunction
+ Definite article
+ Articles
+ Auxiliary verb
+ Active and passive voices
+ Adjectives
+ Exclamation
+ Gerund
+ Onomatopoeia
+ Orthographic accent
+ Possessive adjective
+ Demonstrative adjective
+ Demonstrative pronoun
+ Determiner
+ Expressions