I see, this have been really helpful I'm having a test this Saturday, so I'm sure I won't doubt as much as before when deciding which particle to use . Thank you both kindly for your help

Thank you for the detailed description of 助詞. I would like to add a little that I know about the difference between は and が: Using "は" is fairly easy. You place "は" after the subject of a sentence which simply states what the subect does or is: わたしは学生です。 (I am a student.) かれは音楽家です。(He is a musician.) あなたは日本人ですね？(You are Japanese, aren't you?) 武君は花瓶を壊しました。 (Takeshi broke a vase.) お父さんは新聞を読んでいます。 (Father is reading a newspaper.) If you replace は with が in the above sentences, but it puts emphasis on the subject. Very often, it implies that there might be other choices for the subject. わたしが学生です。- It is I who is a student. 彼が音楽家です。- It is he who is a musician. あなたが日本人ですね？ - It is you who is Japanese, isn't it? 武君が花瓶を壊しました。- It is Takeshi who broke the vase. が is also used after a subject of a clause in a compound sentence: 武君は花瓶を壊しました。＋　見ました。= 武君が花瓶を壊したのを見ました。- I saw that Takeshi broke the vase. が is also used after a subject of a descriptive sentence as a result of observation: For an example, a teacher asked students to describe what they see in a picture. A student who saw an image of a father reading a newspaper would respond, お父さんが新聞を読んでいます。 For the most, we use を after an object. が or　は after an object place an emphasis on the preceding word, and slightly change the implication of a sentence. わたしは猫を飼っています。 - I have a cat as a pet. あなたが好きな動物はどれですか？ - What is the animal that you like? わたしは猫が好きです。 - I like cats (of all the animals/compared to other animals). あなたは猫が好きですか? - Do you like cats? わたしは猫は嫌いです。 - I don't like cats (but I like other animals). あなたは何を勉強していますか? - Wat are you studying? わたしは数学を勉強しています。 - I'm studying math. わたしは数学が苦手です。- I am not good at math. わたしは数学は苦手です。 - I am not good at math (but I am OK with other sujbects).

Oh, almost forgot. と functions a lot like "and" in English. However, it can only be used to connect nouns together. It can not be used to join adjectives, adverbs, verbs, or sentences.

Some more particles~ で - Location where an action takes place. Example: うちで日本語のべんきょうをします。 (House <- で <- Japanese Language <- study) で - Instrument used to carry out an action.　　Example:　ナイフでオレンジを切ります。　(knife <- で <- orange <- を <- to cut) で - Reason or cause of an action. Example: ビジネスでアリゾナへ来ました。　(business <- で <- Arizona <- へ　<- Came to) も - Too, as much as, as many as. Example： A: 私は日本人です。 B: 私も日本人です。 (Person A states they are Japanese. Person B then states that they also are Japanese.) 八時間もべんきょうしました。 (8 hours <- も <- Study) も - Both A and B or neither A nor B. Example: ブラワンさんはすしもすきやきも好きです。　(Brown-san <- は <- sushi <- も <- sukiyaki <- も <- like) と - Together with. Example: トマトとセロリとレタスがあります。 (Tomato <- と <- celery <- と <- lettuce <- が <- exists.

Wow, thank you very much, it's much more clearer now, specially the use of を, I'll practice deciding between は and が. =D