1. When I arrived at this house, he was still sleeping.

2.She was watering the flowers in her garden while her next door neighbor was chatting with her over the fence.

3.As we were crossing the street ,we saw an accident

4.The bell was ringing while Tom was taking a bath

5.she heard a noise and got out of the bed when the door was opening

6.The children were playing football when their mother came back

7.who is the man that you are talking to? I saw him at the gate when I came in

8.we were waitingfor the bus when he passed in his car and offered us a lift

9.I was very tired because I worked all day yesterday

10.when the students heard the bell ,they got up and left.

1,arrived , was still sleeping.

2,was watering/was chatting 

3,were crossing/saw 

4,rang/was talking

5,.heard/got/was opening

6,were playing/came.

7,is/are talking/saw/came

8,were waiting/passed/offered

9,was/worked

10,heard/got up/left