EDFA在应用中应该注意的问题有（）
A.非线性问题
B.带宽问题
C.光浪涌问题
D.色散问题
参考答案：A, B, C, D
物质的量之比为2︰5的锌与稀硝酸反应，若硝酸被还原的产物为N2O，反应结束后锌没有剩余，则该反应中被还原的硝酸与未被还原的硝酸的物质的量之比是
A．1︰4
B．1︰5
C．2︰3
D．2︰5
Fair and (73) competition in government procurement around the world is good business and good public policy．Competitive pricing，product (74) and performance improvements result from competitive practices and help ensure that government authorities get the best (75) for the public they serve．
A．open
B．continue
C．dependent
D．reliable
