【单选题】A technician needs to add network capacity. However, when plugging a second switch into the first switch, there is no link light. Which of the following is the cause of this situation?()
【单选题】I live in a faraway village. There is no wireless network or telephone signals. I am a farmer. I work hard, but I only get 2000 dollars a year. If I want to contact my friends in Shanghai, I will ____...