It is hard to track the blue whale, the ocean’s largest creature

It is hard to track the blue whale, the ocean’s largest creature, which has almost been killed off by commercial whaling and is now listed as an endangered species. Attaching radio devices to it is difficult, and visual sightings are too unreliable to give real insight into its behavior.
【正确答案】：追踪海洋中的巨无霸生物蓝鲸绝非易事。由于过度的商业性捕杀，蓝鲸已将近灭绝，现已被列为濒危物种。在蓝鲸身上安装无线电监控器很困难，而肉眼的观察又不太可靠，无法让人真切洞悉其生活习性。