"Il faut" is used to express what is necessary or required, while "il ne faut pas" is used to express what is not allowed or should be avoided. For example, you would use "il faut" to say "il faut étudier pour réussir" (it is necessary to study to succeed), and "il ne faut pas" to say "il ne faut pas fumer dans ce lieu" (smoking is not allowed in this place). These expressions are used to give advice, make recommendations, or set rules. **

"Il faut" is used to express a general necessity or obligation, while "il faut que" is used to introduce a specific action or event that is necessary or required. For example, "il faut manger" means "it is necessary to eat" in a general sense, while "il faut que tu manges" means "you need to eat" in a specific sense. "Il faut" is used to make a general statement about what is necessary, while "il faut que" is used to specify what needs to be done. **

"Il faut" is a common expression in French that is used to convey the idea of necessity or obligation. It is followed by an infinitive verb and is used to express what needs to be done or what is necessary in a given situation. For example, "Il faut manger" means "It is necessary to eat." This expression is used to give advice, make suggestions, or express general truths. **

The past tense of "il faut" is "il a fallu." This is the third person singular form of the verb "falloir" in the past tense. It is used to indicate that something was necessary or required in the past. For example, "Il a fallu partir tôt ce matin" means "It was necessary to leave early this morning." **

"We say 'il faut' in French instead of 'on doit' because 'il faut' is a more common and idiomatic expression in the French language. It is used to convey the idea of necessity or obligation in a more formal and impersonal way. On the other hand, 'on doit' is more direct and personal, implying a specific obligation or duty. Therefore, 'il faut' is preferred in a wider range of contexts and is considered more polite and appropriate in formal or general statements." **

The phrase "il faut" is used in French to express the idea of necessity or obligation, while "on doit" is used to express the idea of duty or responsibility. The use of "il faut" is more common because it is a more general and impersonal way of expressing necessity, whereas "on doit" is more specific and implies a direct responsibility or obligation. Additionally, "il faut" is a fixed expression in French, while "on doit" can be more easily replaced by other phrases or constructions. Therefore, "il faut" is used more frequently in written and spoken French. **

As an AI language model, I don't have personal experiences or the ability to read books. However, "Il faut sauver Saïd" is a French novel written by Brigitte Smadja. It tells the story of a young boy named Saïd who is struggling to find his place in the world. The novel addresses themes of identity, immigration, and belonging, and has been well-received for its powerful storytelling and thought-provoking content. If you have read the book, I would love to hear your thoughts on it! **

"Il faut" and "on a besoin" both express a need or necessity in French, but they are used in slightly different contexts. "Il faut" is used to express a general necessity or obligation, while "on a besoin" is used to express a specific need or requirement. For example, "Il faut manger pour vivre" (One must eat to live) expresses a general necessity, while "On a besoin de nourriture pour survivre" (We need food to survive) expresses a specific need. **