YOU SAID:

I was walking down the street when I saw a hat in the middle of the road

INTO JAPANESE

道路の真ん中で帽子を見たとき、私は通りを歩いていた

BACK INTO ENGLISH

When I saw a hat in the middle of the road, I was walking in the street

INTO JAPANESE

道路の途中で帽子を見たとき、私は通りを歩いていた

BACK INTO ENGLISH

I was walking in the street when I saw a hat in the middle of the road

INTO JAPANESE

私は道路の真ん中に帽子を見たときに通りを歩いていた

BACK INTO ENGLISH

I was walking along the street when I saw my hat in the middle of the road

INTO JAPANESE

私は道の真ん中で私の帽子を見たときに通りを歩いていた

BACK INTO ENGLISH

I was walking along the street when I saw my hat in the middle of the road