Lesson 17 - Give me this
You have already learned the four pronouns kore, sore, are, and dore, and you have also learned various commands with kudasai on the end. Now we will learn one more command. To say "Please give me this", you would say Kore o kudasai. The particle o identifies the direct object. You may replace kore with any pronoun or noun of your choice to ask for something. Be aware, though, that o kudasai cannot be used alone; it would make no sense. You need a direct object in order to use that phrase.
You can also use the o particle with other commands. For example, if you wanted to say "Open the door", it would be DOA o akete kudasai. Other examples are Namae o kaite kudasai (Please write your name), Hon o yonde kudasai (Please read the book), and Hako o shimete kudasai (Please close the box), just to say a few. Try out several different variations of these to get different commands.
を O- direct object particle