题干
Guangzhou, Shanghai and other big cities are exciting places ______.
A：work
B：working
C：work in
D：to work in
答案(点此获取答案解析）
D
Guangzhou, Shanghai and other big cities are exciting places ______.
A：work
B：working
C：work in
D：to work in
，则它的定义域为（ ）