Portuguese Grammar Essentials is an Android app designed to help students review essential grammar topics in the Portuguese language. The app, developed by MDonch, is completely free, works offline, and has no ads. It includes comprehensive grammar topics, quick reference tables for verb conjugations, and quick access to specific subtopics.

The grammar topics covered in the app include orthography, articles, nouns, adjectives, adverbs, prepositions, pronouns, verb variations, regular verbs, auxiliary verbs, irregular verbs, conjunctions, numbers, time, and dates. Each lesson has quick navigation links at the top to help you find the information you need quickly.

In addition to the comprehensive grammar topics, the app also allows users to suggest new study topics for the developers to add. It also includes a list of recommended study materials to assist your learning.

Overall, Portuguese Grammar Essentials is a useful app for students of the Portuguese language who want to review essential grammar topics. It's easy to use, contains valuable information, and is completely free.