单项选择题 While performing a preventative maintenance check on a personal computer, a technician notices thatseveralunused expansion card slots have open ports. Which of the following BEST describes why the covers for these card slots should be reinstalled?（）

多项选择题 Which of the following are valid ports for printing over a network? （）

单项选择题 Which of the following types of portable media offers the LARGEST storage capacity?（）