【判断题】EPON系统中下行采用1490nm/上行采用1310nm的波长进行双向传输。()
【简答题】EPON下行信号的传输采用 方式,上行信号的传输采用 方式。
【单选题】The local historians believe that McDonald' real purpose is ___the history.
【单选题】Historians using Model A believe that ______.
A.
history is a record of progress
B.
things are getting worse over time
C.
everyone currently alive is not able to rise above the level of people who are dead
【单选题】Historians using Model C believe that ______.
A.
progress is inevitable
C.
periods of progress and achievement are followed by periods of decay
【判断题】1993年,我国精神疾病流行病学调查显示,我国患有精神病患者概率是1.5%。
【单选题】固定铅笔和手指的执笔器、固定在头上或手腕上的翻书装置等特殊器具,是用来帮助下列哪一类儿童的学习和活动的( )
【简答题】Historians believe that the constitution was __________ by King Alexander.