YOU SAID:

suddenly as i was walking down the street i stumbled apon a burger

INTO JAPANESE

突然私が通りを歩いているとき、私はハンバーガーを偶然見つけました

BACK INTO ENGLISH

Suddenly when I was walking down the street, I happened to find a hamburger.

INTO JAPANESE

通りを歩いていたとき交通事故を見かけた。

BACK INTO ENGLISH

While I was walking down the street, I saw a traffic accident.

INTO JAPANESE

通りを歩いていたとき交通事故を見かけた。

BACK INTO ENGLISH

While I was walking down the street, I saw a traffic accident.