1. When I saw him yesterday afternoon, Tom and his father was jogging in the park. (thì quá khứ tiếp diễn diễn tả 1 hành động đang xảy ra thì có hành động khác xem vào: S + was/were + V-ing)

2. Before Jim helped his mon with the household chore, he had fulfilled all his assignments. (Thí quá khứ hoàn thành diễn tả 1 sự việc xảy ra trước 1 sự việc nào đó trong quá khứ: S + had + V quá khứ phân từ)

3. Only after talking to his parents did she make her decision. (câu đảo ngữ với Only after: Only after + N/V-ing/mệnh đề + trợ động từ + S+V)

1. When I saw him yesterday afternoon, Tom and his father was jogging in the park.

* Diễn tả 1 hành động đang xảy ra thì hành động khác xem vào

⇒Cấu trúc: S + was/were + V-ing

2. Before Jim helped his mon with the household chore, he had fulfilled all his assignments.

* Dấu hiệu nhận biết: Before.

⇒ S + had + PII

3. Only after talking to his parents did she make her decision.

⇒ Cấu trúc: Only after + N/V-ing + Trợ động từ + S+ V nguyên thể