Решение:
1. Tom always invites his friend Sam to his birthday party.
- Отрицание: Tom doesn't always invite his friend Sam to his birthday party.
- Общий вопрос: Does Tom always invite his friend Sam to his birthday party?
- Специальный вопрос: Who always invites his friend Sam to his birthday party?
2. Nelly is writing a birthday card now.
- Отрицание: Nelly isn't writing a birthday card now.
- Общий вопрос: Is Nelly writing a birthday card now?
- Специальный вопрос: What is Nelly writing now?