请选择ABCD2B/o7M:^9m6H;I)tListen! She____ in the classroom.0l6J4b7b.l:W
A. is singing0l6J4b7b.l:W
B. sing0l6J4b7b.l:W
C .to sing0l6J4b7b.l:W
D. is sing0l6J4b7b.l:W