Кто знает английский, помогите!

Надо выбрать одно из двух. 

1.I was seeing/saw a friendly dog while I was walking/walked to work today.

2. Yesterday, he was leaving / left  work and took/was taking the bus straight home.

3. They were going/went to a birthday party last Saturday night.

4. He was sleeping/slept when Ann was calling/called for help.

5. Nathan was walking/walked to school when he was meeting/met Tom.

6. Last year we were staying/stayed in a luxurious hotel in Mexico city.

7. She was cooking/cooked at 5 pm yesterday afternoon when I called.