Eurypterida
板足鲎类
🗣️ 情景例句
You must be very tired after the journey.
旅行之后，您一定累了吧！
Don't forget to help him.
不要忘记帮助他。
Two factors weigh heavily against the effectiveness of scientific research in industry.
两个因素严重地影响工业里科学研究的效果：