通风系统阻性消声器的消声性能为()。

Estimating schedule activity costs involves developing an (74) of the cost of the resources needed to complete each schedule activity．

A．accuracy

B．approximation

C．specification

D．summary

A．accuracy

B．approximation

C．specification

D．summary

Estimating schedule activity costs involves developing an(69)of the costs of the resources needed to complete each schedule activity. Cost estimating includes identifying and considering various costing alternatives. For example, in most application areas, additional work during a design phase is widely held to have the potential for reducing the cost of the execution phase and product operations. The cost estimating process considers whether the expected savings can offset the cost of the additional design work. Cost estimates are generally expressed in units of(70)to facilitate comparisons both within and across projects.The(71 )describes the business need, justification, requirements, and current boundaries for the project. It provides important information about project requirements that is considered during cost estimating.

A．accuracy

B．approximation

C．specification

D．summary

Estimating schedule activity costs involves developing an (1) of the cost of theresources needed to complete each schedule activity. Cost estimating includes identifying and considering various costing alternatives. for example, in most application areas, additionalwork during a design phase is widely held to have the potential for reducing the cost of the execution phase and product operations. the cost estimating process considers whether the expected savings can offset the cost of the additional design work. cost estimates are generally expressed in units of (2) to facilitate comparisons both within and across projects.the (3) describes important information about project requirement that is considered during cost estimating.

空白（1）处填（）

A. accuracy

B. approximation

C. specification

D. summary

（71）

A．activity duration estimating, schedule developing, activity resource estimating

B ． activity resource estimating, activity duration estimating, schedule development

C．schedule developing, activity resource estimating, activity duration estimating

D．activity resource estimating, schedule developing, activity duration estimating

A.activity duration estimating, schedule developing, activity resource estimating

B.activity resource estimating, activity duration estimating, schedule development

C.schedule developing, activity resource estimating, activity duration estimating

D.activity resource estimating, schedule developing, activity duration estimating

（71）

A．activity duration estimating, schedule developing, activity resource estimating

B ． activity resource estimating, activity duration estimating, schedule development

C．schedule developing, activity resource estimating, activity duration estimating

D．activity resource estimating, schedule developing, activity duration estimating

Parametric cost estimating involves

A.using the WBS to do bottom up estimates

B.defining the perimeters of the life-cycle

C.calculating the individual estimates of work packages

D.using a statistical model to estimate costs

E.A and C

101 Parametric cost estimating involves

A. using the WBS to do bottom up estimates

B. defining the perimeters of the life-cycle

C. calculating the individual estimates of work packages

D. using a statistical model to estimate costs

E. A and C

19 Parametric cost estimating involves

A. using the WBS to do bottom up estimates

B. defining the perimeters of the life-cycle

C. calculating the individual estimates of work packages

D. using a statistical model to estimate costs

E. A and C