该州十一所学校是用一种濒临灭绝的海洋动物——海牛来命名的.Eleven honor the manatee, an endangered sea animal found in that state.我们看了海豚 、 海牛 、 海狮和鲸的表演.We watched dolphin, manatee, sea lion and whale shows.海象的外形是从海牛物种里演化而成.The shape of Walrus evolved...
A pair of teenage boys were smoking cigarettes...两个十来岁的男孩正在吸烟。Most pregnant women remain off cigarettes while carrying the child.大多数孕妇都在孕期戒了烟。The risk of developing heart disease increases with the number of cigarettes s...
分析了摆动从动件盘形凸轮机构的压力角与基本尺寸之间的关系.The relationship of cam with oscillating followers pressure angle and radius of basic circle were analyzed.凸轮传动结构简单、紧凑,能方便实现从动件预期的运动规律.The structure of cam transmission is simple and compact ...