What is grammatical gender?
Every Portuguese noun falls into one of two grammatical categories, called masculine and feminine. The categories are so called because nearly all nouns denoting male beings are masculine, and nearly all nouns denoting female beings are feminine. But all other nouns – those denoting inanimate objects, abstract concepts, etc. – also belong to one of these categories, so, for example, carro ‘car’, calor ‘heat’ and restante ‘remainder’ are all masculine, while mesa ‘table’, idade ‘age’ and decisão ‘decision’ are all feminine.
任何一个葡萄牙语名词都被归类于语法上的两个类别的其中一个，他们是阳性和阴性。之所以被这样分类，是因为所有指示为雄性的名词都被都是阳性的，而所有指示为雌性的名词都是阴性的。但是其他的名词，那些指示为无生命的物体，例如抽象概念等，都被划分阳性和阴性的分类。例如，carro ‘car’‘卡车’ calor ‘heat’‘热’和restante ‘remainder’‘提示’都是阳性的，而mesa ‘table’‘表格’, idade ‘age’ ‘年龄’and decisão ‘decision’ ‘决定’ 都是阴性的。
Except in the case of nouns denoting living beings, there are no semantic clues to the gender of a particular noun. You simply have to memorize the gender of each new noun you learn, but this task is made considerably easier by the fact that certain endings are indicative of a particular gender
Grammatical gender is crucial in Portuguese because articles, adjectives, possessives,demonstratives and pronouns have to agree in gender with the noun they are accompanying or replacing, which in most cases means their form or ending changes according to whether the noun is masculine or feminine.