2. Have you ever won a competition? No, I have not
3. Has your best friend ever cooked at your house? Yes he has
4. Have you ever drunk fresh lemonade? No, I have not

Ответ:

2. Have you ever won a competition? No, I haven't.

3. Has your best friend cooked at your house? Yes, he has.

4. Have you ever drunk fresh lemonade? No, I haven't