Eurypterida
板足鲎类
🗣️ 情景例句
I want to pick up the car tomorrow morning at seven. Are you open then?
我想在明天早上7点提车。那时你们开门了吗？
I think it's going to take too long.
我认为它将花很长时间。
a wave length (the horizontal distance between two wave crests),
波长（两个浪峰间的水平距离）