Italian has a definite article before names of substances and abstract nouns: Sugar is white Lo zucchero è bianco. Patience is a virtue La pazienza è una virtù.
Italian has a definite article before plural nouns even when they refer to a whole class of people or things: Italians are usually friendly people Gli italiani di solito sono persone amichevoli. Dogs have four legs I cani hanno quattro zampe.
Italian has a definite article before geographical names of countries, regions, mountains etc.: Lake Maggiore is between Piedmont and Lombardy Il Lago Maggiore è tra il Piemonte e la Lombardia.
Italian has a definite article before languages: She speaks Italian and French Parla l'italiano e il francese.
Italian has a definite article before ailments: He has a sore throat Ha il mal di gola. They're in bed with flu Sono a letto con l'influenza.
Italian has a definite article before colours: Our favourite colour is yellow Il nostro colore preferito è il giallo.
To describe jobs in Eng. you use "to be" and the indefinite article; It. uses "fare" ( do, make) and the articolo determinativo: He's a shopkeeper Fa il bottegaio.
Italian has a definite article before sports and games: He likes tennis very much Gli piace moltissimo il tennis. Golf is not very popular in Italy Il golf non è molto diffuso in Italia.