1. Have they installed a new app?
Yes, they have.
2. Has your brother downloaded three videos?
Yes, he has.
3. Have you and your cousins done any searches for your homework?
No, we haven't. (No, my cousins and I haven't)
4. Have you logged on to your computer?
Yes, I have.
5. Has Stella deleted this email?
No, she hasn't.
