单项选择题 A technician needs to assign a default subnet mask for a class B network to a network device that was just installed. Which of the following would the technician use?（）

单项选择题 A technician notices that there is a second partition on the primary hard drive. This partition is not assigned a drive letter and is not accessible from Windows. Which of the following is the MOST likely explanation for this extra partition?（）

多项选择题 Which of the following commands verifies connectivity between two hosts?（）