请保持地方清洁, 并于使用后把所有废物带离中心.Please keep the place clean, and throw away any garbage.椭圆越扁平,两焦点之间的距离越远,每个焦点离中心的距离也越远.The flatter the ellipse the farther apart the foci and the farther each focus the center....
珊瑚是由某些水螅体构成的.Coral is formed by certain types of polyp.水螅虫类生命循环中的无性生殖水螅虫.The asexual polyp in the life cycle of a hydrozoan.在南极边的威德尔海,一只水螅水母伸展它的冷光触须.A hydromedusa spreads its luminescent tentacles in the Weddell Sea near...