42、But the engine () out suddenly

228、An essential step in problem is to identity the underlying abstract problem devoid of all unnecessary detail.

227、Hard disk technology has steadily improved to keep pace storage demand.

226、 the process has no print heads that move or print hammers that fire, the result is high speed and quiet operation.

225、The numeric keypad includes the mathematical keys found on a calculator.

224、They can be used for common commands such as “Print” or “Quit Program”.

223、Radio frequency

222、Transmission media

221、Physical layer

220、Wide area network

219、Store-and-forward