Ответ:

  1. Leo, Lana want to come to your party.
  2. OK, but we need to buy some food!
  3. She needs to go to bed.
  4. Because she wants to go to Istanbul in July.
  5. I want to go to their concert in July!
  6. I need to clean it.
  7. Do you want to go to the cinema?

С подлежащими I, you, we, they используются need/want, а с he, she, it — needs/wants. После Do употребляется начальная форма глагола.