1.They (are running) on the playground (对括号部分提问）
（ What ） （are ）they ( doing )on the playground?
2 They are having a basketball game on the playground(改为否定句）
They (aren't ) (having )a basketball game on the playground.
3 He's studying English in his room.(改为一般疑问句并作否定回答）
（ Is ）he ( studying )English in his room?(No )he (isn't ).
4Wang Wei is writing a letter to (his friend ) 对括号部分提问
（ Who/Whom ） （is ）Wang Wei ( writing ) a letter to?
5My father is at work now(改为同义句）
My father (is ) (working )now