Question

【题目】The girl is often heard happily in her home.
A.sing
B.to sing
C.singing
D.sings

Answer 1

【答案】B
【解析】句意：这个女孩经常被听到在她的房间里快乐的唱歌。hear sb. do sth,听见某人做某事，当这个句型用于被动结构中的时候，动词原形前要加上to。故答案选B。