5. When Tom was a teenager, his hobby ___________ (be) horse riding. 6. Alice often does judo at 5 p.m. every day, but today she ___________ (do) some homework.

Ruby

5. When Tom was a teenager, his hobby was horse riding.

→ Dùng was (quá khứ đơn) vì hành động xảy ra trong quá khứ.

6. Alice often does judo at 5 p.m. every day, but today she is doing some homework.

→ Dùng is doing (hiện tại tiếp diễn) vì "today" chỉ hành động đang diễn ra trong hiện tại, khác với thói quen thường ngày.