Exercise 1: Hãy viết: - số 1 trước các câu kể lại 1 việc đang tiếp diễn tại một thời điểm trong quá khứ. - số 2 trước các câu diễn đạt một việc đang tiếp diễn thì bị 1 việc khác xảy ra chen ngang - số 3 trước câu kể hai hay nhiều hành động diễn ra song song trong quá khứ. 3 e.g.: He was studying English while she was studying Math. 1 e.g.: We were going to the cinema at 8 pm yesterday. 2 e.g.: I was taking a shower when the phone rang. I was watching TV while Jenny was cooking. Katherine was working in her office at 7 pm yesterday. Jack and Jill were having dinner while it was raining heavily outside. They were walking in the park at this time last week. It was snowing outside when the children were playing in the living room. Jamie and I were going shopping together at this time last month. My friend was doing his homework when his mom came in. Thomson was doing the housework when Jessica was watching TV. I was watching “Harry Potter” at 2 am yesterday. Kate was listening to music when the light went off.