YOU SAID:

I was walking the dog when I spotted my teacher in the park.

INTO JAPANESE

私は公園で私の先生を見つけたとき、私は犬を歩いていました。

BACK INTO ENGLISH

When I found my teacher in the park, I was walking the dog.

INTO JAPANESE

私は公園で私の先生を見つけたとき、私は犬を歩いていました。

BACK INTO ENGLISH

When I found my teacher in the park, I was walking the dog.