1.
A:What were you doing at o'clock yesterday afternoon?
B:I was listening to a lecture.
A:Was it raining when you took your sister to the hospital after the lecture?
B:Yes,and it was raining heavily.(No,it was not,but the ground was wet.)
2.
A:What were you doing when I called you yesterday evening?
B:I was doing an experiment in the lab.
A:Do you know what didi Li Min do on Saturday?
B:She said she was engaged in a design all day on Saturday.