So biologists were delighted early this year when, with the help

So biologists were delighted early this year when, with the help of the Navy, they were able to rack a particular blue whale for 43 days, monitoring its sounds. This was possible because of the Navy’s formerly top-secret system of underwater listening devices spanning the oceans.
【正确答案】：今年年初，在海军的大力协助下，生物学家们通过声音监听的方法对一只蓝鲸实施追踪达43天，着实让他们兴奋不已。这次成功所仰仗的是美国海军设置在各大洋的水下监听系统，而这些系统过去曾经属于绝密。