Only then do they close in behind the herd. 这时他们才从背后接近野牛群
The calf must stay close to its protectors... 小象不能掉队
The males stay as close to the female as possible 雄鲸尽可能靠近雌鲸
He's never seen a Doedicurus up close, 它从未如此近距离见过巨犰狳
they pierce the surface at close to 90 kilometers an hour. 以接近每小时90公里的速度刺入水面
was built on the close relationship between flowers and their insect pollinators. 以花与昆虫授粉者的密切关系为基础