2. I (not to eat) ice cream every day. I (not to eat) ice cream now. I (not to eat) ice cream tomorrow. I (not to eat) ice cream yesterday.

Решение:

1. I do not eat ice cream every day. (Present Simple, регулярное действие)
2. I am not eating ice cream now. (Present Continuous, действие в момент речи)
3. I will not eat ice cream tomorrow. (Future Simple, отказ/план)
4. I did not eat ice cream yesterday. (Past Simple, действие в прошлом)

Ответ: do not eat; am not eating; will not eat; did not eat.