问题补充:
John usually relaxes himself by after he finishes his homework.
A. going online
B. played soccer
C. listen to music
D. to watch TV
答案:
(答案→)A. going online
B. played soccer
C. listen to music
D. to watch TV
解析:句意:John做完作业后经常上网来放松自己。介词by,表示通过某种方式,后面接动词的ing形式,故选A。