YOU SAID:

I pet the dog last week

INTO JAPANESE

先週犬を撫でた

BACK INTO ENGLISH

I petted a dog last week

INTO JAPANESE

先週犬を撫でました

BACK INTO ENGLISH

I petted a dog last week.

INTO JAPANESE

先週、犬を撫でました。

BACK INTO ENGLISH

I petted a dog last week.