I really like this song as it is often heard everywhere in China.A. singingB. sungC. havin

问题补充：

I really like this song as it is often heard everywhere in China.

A. singing

B. sung

C. having sung

D. to sing

答案：

A. singing

(答案→)B. sung

C. having sung

D. to sing

解析：考查非谓语。Hear+宾语+宾补，宾语hear与 宾补sing 构成动宾关系所以用过去分词sung。