Adopting is a way to vote "this sentence is correct". It is also an occasion to check the sentence and correct it if there is a mistake.
So if you want to help us check and correct sentences, then adopt () any "orphan" sentence you see in your native language, and correct it if necessary. Read this for further explanation.
If you see another username appear after adopting a sentence, it means that someone else adopted the sentence very shortly before you did. In such cases, you can try adopting sentences that are several pages away from your current page to reduce the chances of that happening again.