🔹 S + was/were + V-ing→ She was cooking when I arrived.
🔹 S + was/were + not + V-ing→ They weren’t watching TV at 9 p.m.
🔹 Was/Were + S + V-ing?→ Were you sleeping when I called?
At + giờ + quá khứ: at 8 p.m. last night
When, while, as
All + thời gian quá khứ: all day yesterday, all night
Không dùng thì này với các động từ chỉ trạng thái (know, like, believe, understand...) → ❌ I was knowing the answer.
» GRAMMAR E-BOOK - SÁCH NGỮ PHÁP