Poid
形心(曲线), 拟正弦线, 膺正弦线, 瞬心轨迹
🗣️ 情景例句
at all the great places in the city.
去城市所有的好地方看看。
She looks so pale, she must be ill.
她脸色很苍白，一定病了。
The firm closed down because there wasn't enough demand for its product.
工厂关门了，因为产品供过于求。