问题 问答题

【背景资料】

某工程建设项目的施工网络计划如图1所示。在施工过程中,由于业主直接原因、不可抗力因素和施工单位原因列各项工作的持续时间产生一定的影响,其结果如下表(正数为延长工作天数,负数为缩短工作天数所示),网络计划的计划工期为84天。由于工作的持续时间的变化,网络计划的实际工期为89天,如施工网络计划图2所示。

问题:1.确定网络计划图1和图2的关键线路。

2.延长合同工期18天和按实际工程延长合同工期5天是否合理为什么

3.监理工程师应签证延长合同工期几天合理为什么(用网络计划图表示)

4.监理工程师应签证索赔金额多少合理为什么

答案

参考答案:

1.图1的关键线路是B→C→E→G或①→③→④→⑥→⑦;图2的关键线路为B→D→F→H或①→③→④→⑤→⑦。关键线路的确定方法,可利用已给出的每个工作的最早开工时间。因计划工期已给出,则以终点节点为完成节点的工作,其最迟完成时间等于计划工期。工作的最迟完成时间减去本工作的持续时间即为该工作的最迟开始时间。如此按顺序从右向左逐个工作进行计算,即可得出每个工作的最迟开始时间。已知计划工期等于计算工期,则工作的最迟开始时间与最早开始时间相等的工作,其总时差为零,即为关键工作。从网络计划的起点节点到终点节点全是关键工作组成的线路,即为关键线路。亦可利用其他方法,如标号法,或找出网络计划的四条线路中总持续时间最长的线路即为关键线路。 

2.要求顺延工期18天不合理。因业主原因和不可抗力因素对工作持续时间的影响不全在关键线路上。要求顺延工期5天也不合理。因其中包含了施工单位自身原因所造成的工作持续时间的延长和缩短。 

3.由非施工单位原因造成的工期延长应给予延期。如下图所示。签证顺延的工期为(90-84)天=6天。 

4.只考虑因业主直接原因所造成的经济损失部分:(800+600+2×500+3×800+3×500)元=6300元

阅读理解

It’s important to learn about protecting our environment. Here is a 5R rule for us:

1.  Reduce

If you want to reduce waste, you should use things wisely. Millions of trees are being cut down to make paper. If everyone uses a little paper carelessly and throw it out, soon we would not have any trees left. Other things are also being wasted, and people don’t know what to do with the waste in big cities. So it is necessary to reduce the waste

2.  Reuse

You should always think of reusing the usable things before throwing them out. Give your clothes you do not use or the ones which are too small to the poor. With a family, you may pass on such clothes to younger brothers or sisters.

3.  Recycle

Bottles, cans and paper can easily be recycled. By doing so, we save lots of time and money. For example, coke cans are sent to a factory, where they are smashed flat(压平)and melted (融化) and the melted things are made for new coke cans.

4.  Recover

When you buy a box of apples, there may be a few rotten(腐烂的)apples. You have two choices: one is to throw the whole apple away, or you could cut off the rotten parts and eat the good parts. In this way, you are recovering the eatable parts of food.

5.  Repair

If one of the legs of your table is broken, you can repair it instead of throwing it away. If you want to change for better ones, It is better for you to sell the old things or give them to other people who can use them after doing some repair. It is true that North America is a “throw-away” society(社会). But the time has come to change our way of life so that we can protect our environment. Every one of us should try our best.

小题1:_______ can be recycled.

A.Only hard things

B.Many things

C.Few soft things

D.All things小题2:The “recover” rule mainly requires us _______.

A.to throw waste things away

B.to cover waste things with earth

C.to get back the useful parts

D.to throw the whole things away小题3:We can infer(推断) that the writer of this passage may live in _______.

A.China

B.Japan

C.Australia

D.America小题4:Which of the following is true?

A.We will have no resources(资源) of nature unless we can do with the waste.

B.Recycling is the best way to save resources.

C.If we waste less, we can save more resources of nature.

D.More things are wasted in developed countries than in developing ones.

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