M600电源板中下列哪些电源板高度是1U（）
A、PCWAS
B、PCWBS
C、PCWCS
D、PCWDS
参考答案：C, D
Some philosophers insist that one way to________knowledge is through an empirical approach.
A．disseminate
B．classify
C．test
D．acquire
双单体附加系（double monosomic additive line）
