My friend Lisa is good at .A. singB. to singC. singingD. sings

问题补充：

My friend Lisa is good at .

A. sing

B. to sing

C. singing

D. sings

答案：

A. sing

B. to sing

(答案→)C. singing

D. sings

解析：考查非谓语动词。句意为：我的朋友丽莎擅长唱歌。短语be good at意思是“擅长”，at是介词后接名词，代词或动车的ing形式。故选C。