With so many people the Internet it is difficult to see online movies at the same time.A

问题补充：

With so many people the Internet, it is difficult to see online movies at the same time.

A. surf

B. to surf

C. surfing

D. surfed

答案：

A. surf

B. to surf

(答案→)C. surfing

D. surfed

解析：此题考查的是with 的复合结构，so many people 与surf 之间是主谓关系，surfing表示主动进行，因此选C。