I am a new person and my English is not very good, if any statement is not very right, please understand more. The first sentence may be not appropriate.Your Chinese sentence translated into English means “The teacher asked the students to sit on the floor and read”，but the picture shows that only the teacher holds the book and children just listen. Orther sentences are generally no obvious errors. Describe a picture in Chinese, usually in the ongoing tense. So I suggest you add “正在”or"正"in the first,second,fourth and fifth sentence.Such as“老师正拿着书讲一个童话故事”，“老师正在拿书讲一个童话故事” This is my first answer on this app. I hope it can help you.

Hello，i am a native speaker of Chinese. Sorry to say that my English is not good. Hope my suggestions can help you～ 老师正在坐着给学生们(或者是“孩子们”)读书，她正在讲一个童话故事。 小学生们坐在地上听老师读。其中，有三个小女孩笑着看着老师，有一个学生穿着绿色的衣服，还有一个学生穿着紫色的衣服。