用于沥青混合料的配比设计及沥青路面施工质量检验的试验是（）。A.密度试验 B.马歇尔

测量误差分为三类：系统误差、随机误差、疏忽误差。其中（）又可以分为基本误差和附加误差。

2009年是新中国成立              周年，大庆油田开发建设              周年，大庆建市          周年

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A、53 50 30

B、60 30 30

C、60 50 30

D、50 30 30

欺诈案件的调查要多久？

(一)

某工厂正在研究选择具有同一功能的A、B两种机械哪一种有利的问题，两机械的寿命都是7年。初期投资额，A机械为10万元；B机械为14万元。每年的作业费用(假定为每年年末)，A机械为2万元；B机械为0.9万元。该厂拟定的收益率为12%。已知：(P/A，12%，7)=4.564，(F/P，12%，7)=2.211，(A/P，12%，7)=0.21912。回答下述问题：

如果A、B两种机械的寿命不同，应首选( )进行比较。

A．净现值法

B．净将来值法

C．内部收益率

D．净年值法

Most computer systems are (16) to two different groups of attacks: Insider attacks and outsider attacks. A system that is known to be (17) to an outsider attack by preventing.
(18) from outside can still be vulnerable to the insider attacks accomplished by abusive usage of (19) users. Detecting such abusive usage as well as attacks by outsides not only provides information on damage assessment, but also helps to prevent future attacks. These attacks are usually (20) by tools referred to as Intrusion Detection Systems.

A．visit

B．access

C．I/O

D．read/write