71.Which layer-function is mostly implemented in a network adapter（）。

       A．Physical layer and link layer

       B．Network layer and transport layer

       C．Physical layer and network layer

       D．Transport layer and application layer

       72.Software Engineering is best described as（）.

       A．the practice of designing,building,and maintaining off-the-shelf software from prefabricated parts

       B．the practice of designing,building,and maintaining ad-hoc software without the use of formal methods

       C．the practice of designing,building,and maintaining reliable and cost-effective software using standard techniques

       D．the practice of designing,building,and maintaining fast and flexible software specifically for engineering applications

       73.A requirements specification is（）.

       A．a rough list of things that the proposed software ought to do

       B．a precise list of things that the proposed software ought to do

       C．a formal list of things that the proposed software must do

       D．an estimate of the resources（time,money,personnel,etc）which will be required to construct the proposed software.

       74.A critical path for a project is the series of activities that determine（）by which the project can be completed．

       A．the earliest time

       B．The latest time

       C．The total time

       D．the free time

       75.In project time management processes,（）involves identifying and documenting the relationships between project activities.

       A．activity definition

       B．activity sequencing

       C．schedule control

       D．Schedule development