Question

He is singing a song（ in the classroom.）括号部分提问

Answer 1

由于是in the classroom提问，它指地点，所以用where（哪里），where后接Be动词，所以把is提前，后面的就不变。
He is singing a song。
提问in the classroom，就变为Where is he singing a song?
选我吧！打字很辛苦。

Answer 2

Where is he singing a song?

Answer 3

Where is he singing a song?

Answer 4

Where is he singing?

Answer 5

Where is he singing a song? (对地点“in the classroom”提问要用"where")