at this time, however, we do not know if it was the man-made hunt for the mastodons, mammoths and other large animals from the so-called megafauna, which caused them to become extinct and disappear.
可是,我们现在还无法知道这一人造狩猎工具到底是不是造成所谓巨型动物群内乳齿象、猛犸象及其他巨型动物灭绝和消失的原因。
taking the absolute point of view, humans would be justified in allowing any species to become extinct if it would take extraordinary efforts to save it.
如果采取一种绝对的观点,那么,如果挽救某一物种需要作出巨大努力,则人类让这一物种趋于灭绝应该说不无其合理性。
that such a species could be allowed to become extinct is inconceivable—and, as a consequence, a big, expensive programme to save them is running in california.
这种物种可能会濒临灭绝是无法让人相信的——结果,美国加州启动了一个规模浩大且花费昂贵的拯救项目。
the use of ddt caused the peregrine falcon to become extinct throughout much of its normal range throughout the eastern united states.
ddt的使用使得生活在美国东部的猎鹰在其许多正常生活区域内归于灭绝。