单项选择题 A user has purchased a laptop that has no means to charge the battery. Which of the followingwould the user MOST likely purchase?（）

单项选择题 Which of the following is the NEXT step in the troubleshooting theory after identifying the problem?（）

多项选择题 Which of the following network connections would use a standard POTS line to both send andreceive Internet packets?（）