He has come to be recognized as an expert in the problem of overpopulation and food supply.
由于他的經驗促使他終于成為了公認的人口過剩和食物供應問題的專家。
as by falling into inaccessible caves, or into an ice crevasse, like the Siberian mammoths,
如掉進難以到達的洞穴,或掉進冰河裂縫里,或者像西伯利亞長毛象那樣掉進冰窟中,