Answer:
1. Yo pido
2. Tu pides
3. Nosotros sabemos hablar inglés porque lo aprendimos usando internet.
["Lo aprendimos" is in 1st person plural because the subject of the phrase is still nosotros]
4. Ustedes sirven
5. Ellos sirven
6. Ellos conocen cosas sobre otros países gracias al internet.
[Note that you can't say "They know about..." in spanish. You have to add a noun before: "They know things about..."]