There are many ways to ask a question. However, the best way often depends on the situation. Some forms are rather formal -to be used when writing, giving speeches, or at times that you would use vous to address someone. Other forms are ideal for informal situations. Although there are forms which are clearly formal or clearly informal, some forms can be used at anytime and anywhere- whether you are giving a speech to parliament or hanging out with friends.
First, let's look at questions with simple yes/no answers. There are three ways to ask such questions...
Using rising intonation at the end of a sentence is the most common informal form.
Tu es sure ?
Nous avons des biscuits ?
Do you see the whale?
Fronting a sentence with est-ce que, is common in both formal and informal contexts.
Est-ce que je pourrais parler avec Guy ?
Est-ce que je suis fou ?
Est-ce qu'Alphonse est là ?
Maman, est-ce que je peux aller jouer avec Bruno ?
Formal questions are distinguished by the inversion of the subject and verb.
Avez-vous visité la Belgique ?
Êtes-vous prête ?
When a verb ends in a vowel and is followed by il, elle, or on, a 't' is inserted between the verb and the noun.
Mange-t-il de la viande ?
Usually when je is the subject, questions are not formed through inversion execpt with a few short monosyllabic verbs (aller, avoir, devoir, dire, être, and pouvoir) Instead, when je is the subject, questions are typically formed by 'fronting' with est-ce que.
Puis-je parler à Helene, s'il vous plaît ?
Suis-je fou ?
|Est-ce que tu voudrais être ma femme ?
Would you like to marry me (be my wife)?
If the question has a negation, contradict the assumption implied in the question with si...
Tu ne manges pas ? -Si
Merci is equivalent to 'no thank you'.
Tu voudrais du vin ? Merci