1. In front of the building was a supermarket.

2. In front of the building, was a supermarket.

3. In front of the building a supermarket was.

4. In front of the building, a supermarket was.

(Which ones are grammatical?)

3 answers

Only 1 is correct.
Thank you for your help.

1. In front of the building was it.

2. In front of the building it was.

(What about these sentences? Which one is grammatical?)
Neither is correct.