as a result of a heavy workload, the payroll department had trouble finishing analysis by itself
여기서 by itself가 나오려면 주어가 the payroll department여야하자나요
fisnishing이 분사구문이라고 생각되어지구요 그앞에 원래 주어가 the payroll departmen이거엿겟죠???
원문장을 만들어주시면 더욱더 감사드리구요 ㅎㅎ