herding cats 艰巨任务；难以驯服

【例句】
If reform in America is hard, managing the process across dozens of countries is akin to herding cats.
如果美国的改革是困难的，那么管理十来个国家的进程无疑是艰巨任务。

Getting all of the extended family into their right places for the reunion photo was like herding cats!
把所有大家庭成员都安排到合适的地方，拍一张团聚照，简直是个难管的活儿。