He has come to be recognized as an expert in the problem of overpopulation and food supply.
由于他的经验促使他终于成为了公认的人口过剩和食物供应问题的专家。
These friendly dogs, which were first brought from Asia, were used as watchdogs even in Roman times.
那些最先从亚洲引进的狗,待人友好,早在罗马时代就给人当看门狗了。