There are some boys playing football.这句子里面为什么用playing?能否分析下句子成分?

There are some boys running in the playground.对some提问,对some boys提问 there are some differences between the two boys同义句 There are some boys in the classroom 改为否定句 there are some boys ----(swim) in the pool写出原因 改为一般疑问句：There are some games for boys. there are some boys( )(swim)in the river 英译汉：Also there are some boys playing ball games. there are some American Boys in chassis改为单数 Some boys are playing computer and others are draw some pictures there单句改错 which boys are there? There are some differences between the two boys写同义句.The two boys are ____ ____ each other Are there any boys in the playground?no,there aren't some. there are some boys in the park.they are playing soccre.合为一句 there are some boys swimming in the poolswimming 前为什么不加 are? Boys are over there sudu There are three boys in the classroom .There are some libraries in our school .(对斜体部分提问) There are some boys in my class.改一般疑问句怎么改 There are some boys in the park.in the park划线提问