Learn Italian: Devi mescolare il latte e lo zucchero. - You must mix the milk and the sugar.

In Italian, you almost always need definite articles (il, lo, la, etc.) before nouns representing general categories, ingredients, or substances. English often drops "the" in these cases, but Italian requires it!

Why is the article lo used for zucchero instead of il?

You must use lo (and its plural gli) for masculine words that start with the letter "z", or an "s" followed by a consonant (like studente). Since zucchero starts with a "z" and is masculine, it takes lo.

Wait, latte ends in -e. How do I know it takes the masculine article il?

Italian nouns ending in -e can be either masculine or feminine, so their gender just has to be memorized. Latte happens to be masculine. It is always best to learn these words along with their articles, memorizing it as il latte.

Since this lesson is about the pronoun ne, how would I use it if I wanted to say "You must mix some (of it)"?