There are three girls （in） the first picture.为什么这里要用in 而不用at on 或者of

Yes,there are three there are three 的中文 There are three light是什么意思 There is three dollars 还是There are three dollars there are three c----in the family .one is a girl .the other two are boys在横线上天一个单词,是初一上册中的, There are three monkeys.改为一般疑问句 . there are three apples on the desk? there are three books的问句是什么 there are three 什么in the city there are three birds in the There are three _____ of animals There are three ____(policeman)填空 There are three good ways to There are three的上一句是什么? There are three p.in my family there are three of matter 汉语怎么说 There are three p.in my family There are three birthdays in October对three提问