Learn French: Pourquoi est-ce que tu lis ce livre ?

The word pourquoi literally translates to "for what" (pour = for, quoi = what). It asks for the purpose or reason behind an action. When answering a pourquoi question, you will often use the exact grammar from this lesson: pour followed by an infinitive verb (for example, pour apprendre, meaning "to learn").

Why do we use est-ce que here? Can I just say Pourquoi tu lis ce livre ?

You definitely can! Pourquoi tu lis ce livre ? is very common in everyday, casual spoken French. However, adding est-ce que right after the question word (pourquoi) makes the sentence standard and slightly more formal. It is a very reliable structure to learn at this level.

Why does the English translation say "are you reading" when the French just says tu lis?

French doesn't have a separate "am/is/are + -ing" tense like English does. A single French present tense covers both! Tu lis can mean "you read" (a regular habit) or "you are reading" (happening right now). The context of the conversation tells you which one it is.

Why is it ce livre instead of cet livre or cette livre?