The Object Marker を(wo) is often written in romaji as o, much like お.
Generally known as the direct object marker. This is more essentially the thing that receives the action. Since there are various uses for を, it’s easiest to simplify を down to the purpose of action receiving marker.
When using を place it after the thing that is being acted on. Let's look at some examples.
ぼくは スーちゃんに プレセントを あげました。
I gave Sue a present.
ジッミーが ねこを なげた！
Jimmy threw the cat!
ボブくんが ごはんを たべた。
Bob ate rice.
As you can see above the noun, the object, the thing is marked with を.
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Now, there is something called a transitive and intransitive verb that can make this confusing but we will be talking about this towards the end of the challenge. So if a native Japanese person is reading over you shoulder say 「をって、そういう意味だけじゃねーんだろう。」they would be right. There are other ways to use を, but we will touch on that other version later.