Подчеркнуть подлежащее и сказуемое, подписать время глаголов.

Конечно! Вот подчеркнутые подлежащие и сказуемые с указанием времени глаголов:

4. Greg — (learn) to play chess today. (Present Continuous: is learning)

5. It — (rain) at the moment. (Present Continuous: is raining)

6. You — (always/lose) your keys! (Present Simple: always lose)

7. My father — (play) chess when I came back home. (Past Continuous: was playing)

8. I — (have) dinner with my grandparents tonight. (Present Continuous for future arrangement: am having)