问题 问答题

案例四

[背景材料]

某施工单位编制的某工程网络图,如图7-1所示,网络进度计划原始方案各工作的持续时间和估计费用,如表7-1所示。

[问题]

若该网络进度计划各工作的可压缩时间及压缩单位时间增加的费用,如表7-2所示。确定该网络进度计划的最低综合费用和相应的关键路线,并计算调整优化后的总工期(要求写出调整优化过程)。

答案

参考答案:

调整优化过程。

第一次调整优化:在关键线路上取压缩单位时间增加费用最低的F工作为对象压缩2天。

增加费用:2×2=4(万元)

第二次调整优化:A、C、H、J与B、F、J同时成为关键工作,选择H工作和F工作为调整对象,各压缩2天。

增加费用:2×(1.5+2)=7(万元)

第三次调整优化:A、C、H、J与B、F、丁仍为关键工作,选择A工作和F工作作为调整对象,各压缩1天。

增加费用:1×(2+2)=4(万元)

优化后的关键线路为: ①—③—⑥—⑦—⑧(或关键工作为A、C、H、J) 和 ①—②—④—⑦—⑧(或关键工作为B、F、J)

总工期:98-2-2-1=93(天)

最低综合费用:401+4+7+4=416(万元)

阅读理解

“If you want to see a thing well, reach out and touch it!”

That may seem a strange thing to say. But touching things can help you to see them better. Your eyes can tell you that a glass ball is round. But by holding it in your hands, you can feel how smooth and cool the ball is. You can tell how heavy the glass it. When you feel all these about the ball, you really see it.

With your skin, you can feel better. For example, your fingers can tell the difference between two coins in your pockets. You can feel a little drop of water on the back of your hand, too. You can even feel sounds against your skin. Have you wanted to know why some people like very loud music? They must like to feel the sounds of music.

All children soon learn what “Don’t touch!” means. They hear it often. Yet most of us keep on touching things as we grow up. In shops, we touch things we might buy: food, clothes. To see something well, we have to touch it.

The bottom of our feet can feel things, too. You know this when you walk on warm sand, cool grass or a hard floor. All feel different under your feet.

There are ways of learning to see well by feeling. One way is to close your eyes and try to feel everything that is touching your skin. Feel the shoes on your feet, the clothes on your body, the air on your skin. At first, it is not easy to feel these things. You are too used to them.

Most museums are just for looking. But today some museums have things for visitors to touch. Their signs say, “Do touch!” there you can feel everything on show.

If you want to see better, reach out and touch. Then you will really see.

小题1: By touching things ___________.

A.you will have a strange feeling

B.you will learn how to reach out your hand

C.you can see them well

D.you can tell what colors they are小题2:According to the passage, which of the following CANNOT feel things?

A.Skin.

B.Fingers.

C.Feet.

D.Eyes.小题3: Why does it say “At first, it is not easy to feel these things?” Because ___________

A.the things are used by people too

B.people feel the things too much

C.people know how to use the things

D.these things are familiar to you小题4:You can see the sign "Do touch!"_____________________.

A.in every museum

B.in most museums

C.in some museums

D.only in one museum小题5:The best way to see the world well is to ___________________.

A.touch by feeling

B.see or to feel

C.read

D.see and feel

单项选择题