单项选择题
Which of the following components of a laptop is NOT upgradeable?（）
A. Ethernet LAN card B. Motherboard C. Hard disk D. RAM
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?（）
判断题 "Gas-Plasma displays require more power than LCDs."
