He learns English by English songs.A. listenB. listen toC. listeningD. listening to

问题补充：

He learns English by English songs.

A. listen

B. listen to

C. listening

D. listening to

答案：

A. listen

B. listen to

C. listening

(答案→)D. listening to

解析：句意是：他通过听英语歌学习英语。由介词+doing 可知A和C是错误的，由于listen是不及物动词要是有宾语必须加介词 to,所以答案是D。