A community archive interviewed twelve residents about changes in a riverside market. The first draft of its report said, “The archive interviewed twelve residents, six of them kept weekly records.” Readers understood the intended meaning, but the sentence joined two independent clauses with only a comma. The editor offered two repairs. One version read, “The archive interviewed twelve residents, six of whom kept weekly records.” Here, whom linked the relative clause to residents. Another version read, “The archive interviewed twelve residents, and six of them kept weekly records.” Here, and connected two independent clauses, while them referred back to residents. The choice between whom and them was therefore not a matter of formality alone. Each word performed a different structural job. A correct reference did not by itself create a grammatical bridge between clauses.