DTRB位于机柜的DTRU插框中，共有（）个槽位，可插DTRU单板。
A、2
B、4
C、6
D、8
参考答案：C
感染了乙型肝炎病毒，约经2~6个月的潜伏期发病，多为无黄疸型肝炎，黄疸型较少。 ( )
Project work packages are typically decomposed into smaller components called activities to provide a basis for ______, scheduling, executing, and monitoring and controlling the project work．
A．reviewing B．estimating C．auditing D．expecting
