backlog of cases meaning in Chinese

案件积压

These investigators frequently need months to solve crimes , due in part to the backlog of cases at dna testing centers
这些探案人员常常需要数月才能破案，其中部分原因是dna检测中心积压的案件。
These investigators frequently need months to solve crimes , due in part to the backlog of cases at dna testing centers
这些监识人员往往要耗时好几个月才能破案，部分原因是dna检测中心的案子积压太多。
Another justice department study showed that the 50 largest forensic laboratories received more than 1 . 2 million requests for services in 2002 : the backlog of cases for these facilities had doubled in the course of one year
司法部的另一份研究报告指出，在2002年，美国50个最大的?识实验室收到了120万件?定申请；这些实验室的积案，在这一年之内就增加了一倍。