Complex sentence: There is a common driveway about 100 feet from 4th.ave with 2 or three non-descript small manholes in it.there are no markings on the manholes, maybe 1 of them is the entrance.
Split into simpler sentences: There is a common driveway about 100 feet from Fourth Avenue with two or three non-descript small manholes in it. There are no markings on the manholes, and maybe one of them is the entrance.