Quadriennum utile
[法] 四年有效期
🧩 词语组成解析
a. 有用的；有益的
🗣️ 情景例句
It's the world's largest island, but it's also the world's smallest continent.
它是世界上最大的岛屿，同时也是世界上最小的洲。
But you just got here. Can't you stay a little longer?
不过你刚来呀。不能再呆一会了吗？
The currents of air that the walls of the ship direct upwards, as well as in the line of its course, are enough to give the great bird with its immense wings sufficient sustenance and progress.
沿船体的上升的气流和沿航线向前的气流给这种巨翼大鸟以足够的浮力和推力。