祈使句是用来表达命令、请求或建议的句子。通常，祈使句没有主语，并且动词是动词原形。例如，“闭上你的书。”，“请把你的鞋脱下来。”和“不要把你的饮料放在桌子上。”都是祈使句。
在日常生活中，祈使句用于告诉别人该做什么或不该做什么。我们可以使用它们来提供指示或建议，并且在交流中也非常重要。在学习英语时，祈使句是一个非常重要的语法结构，学习者必须对其进行仔细学习和使用，以便能够表达自己的意思和接受别人的指示。
Here are some English sentences describing the appearance of ostrich:
The ostrich is a large, flightless bird with long, powerful legs and a long, curved neck.
Its feathers are soft and fluffy, with a mix of black and white or brown and gray.
The ostrich has a small head with large eyes and a sharp beak.
Its legs are covered with rough scales and end in two-toed feet, with one large toe and one smaller toe.
When threatened, the ostrich will spread its wings and tail feathers to appear larger and more intimidating.
Adult ostriches can grow up to 9 feet tall and weigh up to 300 pounds.
They have a distinctive mating dance, where the male flaps his wings and bobs his head to attract a female.