问题补充:
—How do you think he managed to improve his English in such a short time?
— four hours on it every day.
A. Because of spending
B. To spend
C. By spending
D. Spending
答案:
A. Because of spending
B. To spend
(答案→)C. By spending
D. Spending
解析:问句用到的疑问词是how表方式所以答语要用介词短语By spending作方式状语。句意:你认为他是怎样在短时间内提高英语的?通过每天花费四小时(练习做到的)。