单项选择题
（）allows a laptop to connect to other devices such as monitor, printer, etc.
A.Docking station B.Switch C.Router D.Hub
单项选择题 Which of the following components of a laptop is NOT upgradeable?（）
单项选择题 which of the following actions will you not take before beginning installation or removal of anyNON-PNP hardware device inside the computer case?（）
单项选择题 What does ECC stand for?（）
