1) conoces (tú)
2) sabemos (nosotros)
3) conocen (ustedes)
4) sabe (él o ella)
5) conozco (yo)
6) conocemos (we)
7) sabe (él o ella)
8) conoce (él o ella)
(conocer means to be acquainted with something like a person, book, city, movie, etc)
(saber means to know a fact or you learned a certain skill. you could be talking about knowing the answers, how to play a sport, etc)
reason why is in parentheses, you don't have to write these down but i would like to let you know why these are correct :)
Plural forma de un escritorio