Review the entire משנה דף כג
Learn the גמרא from after the Mishna until the two dots דף כג עמוד ב
Questions:
Does ר’ יהודה בן בבא require a שומירה or the like for an area smaller than 70 square Amos?
According to ר’ יהודה בן בבא how can one carry in an enclosed area larger than 70 square Amos?
Learn תוס’ “ובלבד