You're running the game, so you have to know everything. Well, maybe not everything, but certainly enough to keep things moving. If you know the PCs want to head into the mountains, it's helpful if, ahead of time, you have looked into how mountain travel affects their movement, what it's like to be in the mountains (possibly through some research in an encyclopedia or travel book), and other considerations (climbing gear, mountain encounters, etc.). If you have a chance to try rock climbing, or if you've done it before, so much the better - there's nothing like personal experience to lend realism to your descriptions.

More the point, however, you will want to have prepared as much as you can for the adventure ahead of time. You will want to have figured out what will happen when, the layout of the area (both the large-scale landscape and individual encounter areas), what the PCs will encounter if they go to a particular area, how NPCs encountered in the adventure will react to the PCs, and the events likely to happen (such as a conversation or a fight).

When running a published adventure, this preparation often amounts to reading the material carefully and making notes where you need them. Useful points to note might include any or all of the following:

* Page numbers in the rulebook for rules you know you'll need to reference in a given encounter.
* Changes needed to make the adventure fit into your campaign.
* Changes you want to make to please your tastes or those of your group.
* Preplanned actions you want the NPCs to take in a given encounter (ambushes, dying speeches, spell sequences, etc.).
* Reminders to yourself about rules, adventure structure, events that might occur (such as random encounter checks), or the consequence of certain actions.

If you are designing an adventure on your own, your preparation requires (obviously) a lot more time. This preparation might include any or all of the following elements:

* Maps of the area (large scale) and of specific smaller areas where encounters are likely to occur. These can be as simple and sketchy or as detailed as you like.
* A key to the map or maps detailing special areas and what might be encountered there, including foes, allies, treasure, traps, environmental situations, and possibly even written descriptions of what the PCs see, hear, and experience upon entering an area.
* NPC listings that include their statistics and notes on their potential reactions.
* Bookmarks in the rulebooks (or notes listing page numbers) for rules that might need to be referenced.
* Notes on the overall story or plot of the adventure if it is complex.
* Statistics for any new monsters you're introducing.

This preparation can amount to a lot of work. Not every adventure is going to require reams of notes in order to play. It varies from adventure to adventure and from DM to DM. Not every DM likes to prepare detailed notes ahead of time. Some have more fun if they just "wing it". And sometimes a DM would like to be better prepared, but there just isn't time. Find the style of Dungeon Mastering that suits you best.

Quoi qu'il en soit quelqu'un pourrait il fournir la version en VF de cet extrait du Dungeon Master Guide de D&D 3 ?

Meriadec il s'agissait pas d'échanger de document vu que je l'ai déjà.
Il s'agissait surtout de répondre à une question qu'un membre se pose et que d'autres peuvent se poser en fournissant seulement un extrait en réponse à cette question.
La traduction en français c'est pour ceux qui ne savent pas lire l'extrait que j'ai fourni en anglais.