医药科学
红嘴山鸦
They keep the vegetation low in the winter when the sheep are brought down to lower levels, and they provide food for birds like choughs.
BBC: Bad weather kills half of Welsh wild pony herd
英汉双解词典包含3185865条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。