Try to sing more English songs and you will find it interesting a foreign language.A. lear

问题补充：

Try to sing more English songs,and you will find it interesting a foreign language.

A. learing

B. learns

C. to learn

D. learned

答案：

A. learing

B. learns

(答案→)C. to learn

D. learned

解析：句意：尽量多唱英文歌，你会发现学外语很有趣。这里的it是做形式宾语，真正的宾语是后面的to learn a foreign language这是一个固定的语法形式。而it is…是在it做形式主语的固定句型。所以说，当it做形式宾语时后面不要is,做形式主语时加is(做be动词用）。故选C