Are these __who are playing volleyball over there.为什么D不行~

They are playing volleyball over there They are cleaning the The girls are playing (volleyball) over there.(就括号部分提问) The girls are playing over there.就“are playing” 提问 The girls are playing over there 对are playing提问 look!the boys_(play)over there.为什么是is playing而不是are playing. The children are playing football over there （对are playplayi They are playing over there.的谓语部分是助动词+实意动词构成的吗?为什么 they are over (there )为什么填there 连词成句:playing,they,basketball,are,there,over(.) Where are the children playing games?__________A.Over there A number of boys are playing football over there . look!The children are playing happy over there