Which of the following keys is pressed to enter the Windows boot options after POST?（）

单项选择题A networking device that sends packets to all connections is a:（）

A. gateway.
B. hub.
C. switch.
D. router.

单项选择题A technician is servicing a customer’s color laser printer and notices excess toner in the printer.Which of the following tools would BEST assist the technician in removing the excess toner?（）

A. Damp towel
B. Compressed air
C. Alcohol wipe
D. Computer vacuum

单项选择题Which of the following would BEST provide cooling to a processor?（）

A. Case fan
B. Heatsink
C. Liquid cooling system
D. CPU fan

单项选择题Which of the following should be done FIRST to a hard drive before it is disposed?（）

A. Partition
B. Physical damage
C. Data wipe
D. Format

单项选择题Which of the following has the HIGHEST connection latency? （）

A.Satellite
B.Cable
C.DSL
D.Dial-up