I just bought "The Sims 2 Pets", but when I tried to play it, it 発言しました that I needed to install "The Sims 2" first. I've never played any of the sim games on my computer, so do I need the original "The Sims 2" game to install on my computer first?

Yes. Pets is an expansion pack, not the core game. あなた need the original Sims 2 game first, then あなた can add expansion packs.

Yea, あなた have to buy one of Sims 2 または Sims 2: Double Deluxe. I think my manual says Sims 2 Holiday Edition will work too. あなた have to have one of these games to play with the pets, the pet one is an expansion. All of the other ones, if they arent listed above are expansion packs too. So, あなた can't play with just expansion packs, あなた have to have a base game.

Yeah あなた do... Sims Pets is an extension pack sooo that means that with it あなた can do もっと見る things in the game. Now, there's stuff packs too with allow あなた to have もっと見る objects in the game like the furniture, clothes, etc... So, yes, あなた do need Sims 2

Hope this helps! :)

Yes, anything other than The Sims 2 is an expansion pack and requires The Sims 2 base game to be installed in order to work. So basically, the foundation has to be made first.