如何快速找到雅思阅读答案

　　做MATCHING 题目时，最重要的一点就是找到关键词。拿到一篇文章后，首先浏览文章标题，然后把题目中列出的关键词逐个找到，并将该词所在的句子用线划出。然后，我们就可以根据划线句子的意思与问题给出的备选项进行对照，意思相近或相符的那一句就应该是正确答案。发现两个句子意思相近或相符的关键是找原句中的同义词或近义词，这样就可大大减少阅读量，从而能在较短的时间内找到答案。如果答案不能在出现关键词的句子中找到，就应从该句的上下文中去寻找答案。还有些时候，你会发现关键词在好几个句子中都出现了。这时，你可以将这几个句子都划出来，与备选项中的句子逐个对照，意思相近的就是正确选项。

　　还有一个需要注意的问题是，每选定一个答案后，应把已选好的选项用线划掉，以免影响后面的判断。

　　下面，我们就以下文为例具体进行分析。

　　Geophysics For Utility Location:

　　When It Works - When It Wont

　　Utility companies, construction projects, and highway contractors are often faced with the need to excavate or pipe-jack in the vicinity of known or suspected buried utility lines, drains, or other subsurface structures. In many cases, particularly where they are adjacent to highways, the lateral position of the lines may be documented with reasonable accuracy, but the vertical position, or burial depth, may be uncertain due to changes in grade caused by construction or maintenance performed after the pipes were buried.

　　One way to verify the location of such buried objects is to cautiously dig a trial pit to expose the object in question. However, digging such a pit in or close to a highway is costly because of the need for traffic control, and subsequent reinstatement of the surface to meet the original specification. There is also a substantial risk of accident and personal injury, partly due to the disruption caused to the highway traffic, and partly due to the nature of the work. Where mechanical digging equipment is used, an undocumented or misaligned utility line can easily be damaged if the excavation workers do not observe it. Gas and electricity lines present very obvious safety threats in this situation.

　　These factors have caused utility engineers and contractors to search for alternative methods to locate subsurface structures, often with mixed success. There are several geophysical techniques with proven capabilities in non-intrusive subsurface investigation, but there are less publicized limitations to these methods that potential specifies and users should be aware of if they are to avoid inconclusive or misleading survey reports.

　　Practical Near-Surface Techniques

　　The real driving force behind the development of geophysical survey methods was the search for oil and other valuable mineral deposits. The earlier methods were therefore primarily focused on the detection and identification of relatively large geological formations at depths that were typically measured in several hundreds of feet. Such methods do not have the resolution to detect small objects, such as pipelines and cables, buried only a few feet deep.

　　A few methods, however, were either developed specifically for near-surface work, or were readily adaptable to the task of locating relatively small objects at shallow burial depths. The most commonly used methods in current utility location practice are:

　　 Ground Penetrating Radar

　　 Magnetometer/Gradiometer

　　 Non-contact Conductivity

　　 Specialized Utility Locators

　　These methods have been proven to be very effective in the right conditions, but all have limitations that can render them inconclusive, or worse still, misleading, if used or interpreted by an inexperienced operator.

　　Where soil conditions are appropriate, GPR can provide the most complete and accurate information about buried structures and utility lines, but requires a carefully laid out survey grid or pattern if the maximum accuracy is to be obtained from the survey profiles. GPR will detect non-magnetic or non-conductive lines such as plastic gas pipes.

　　GPR is not suitable for use in locating objects deeper than about 3 feet or so in moist clay or silty clay soils, but since it is measuring soil dielectric properties, it can give useful information about the lateral extent of disturbed soils or backfill areas, even where a utility line is not identified due to signal attenuation.

　　For reconnaissance-level surveys, where it is required to sweep large areas of open land for buried structures, EM conductivity surveys will be much more economical than GPR, but will provide little or no useful depth information. EM will not directly detect non-conductive material such as plastic gas pipe, but will usually identify the conductivity anomaly caused by the backfill around the pipe.

　　Magnetometer, Gradiometer, and electro-magnetic or RF utility locators are generally best employed for tracing the route of a utility line when a physical connection to the line can be made at one end, or in a manhole or trial pit. The methods will not work with plain plastic pipe such as older gas transmission lines. If the plastic pipe has been installed with marker magnets at the couplers, wire markers, or conductive tape laid in the excavation, then these tools might be considered.

　　In the authors experience, the most efficient survey program for a location where no accurate utility information is available is to use EM for an initial search, then use GPR to refine the data in areas where EM indicated conductivity anomalies.

　　A magnetic plastic gas pipe has been developed under the auspices of the Gas Research Institute, and is currently being evaluated under field conditions. If the durability of the material lives up to expectations, and the cost becomes competitive with current gas line products, location of the new lines will be greatly simplified, and current utility location tools will become much more useful.

　　Choose one phrase from the List of phrases to complete each Key point below.

　　The information in the completed sentences should be an accurate summary of the points made by the writer.

　　NB. There are more phrases than sentences, so you will not need to use them all. You may use each phrase once only.

　　Key point

　　1. Utility companies

　　2. Trial pits

　　3. Mechanical digging equipment

　　4. Geophysical survey methods

　　5. GPR

　　6. EM conductivity survey

　　7. The development of a magnetic plastic gas pipe

　　List of phrases

　　A. dig holes to bury utility lines

　　B. are dug to expose subsurface structures

　　C. damages easily undocumented utility lines

　　D. often need to dig holes near some subsurface structures

　　E. are developed to search valuable mineral deposits

　　F. are dug to confirm the location of a subsurface structure

　　G. provides little useful depth information

　　H. always provides the most complete and accurate information

　　I. can detect very small objects

　　J. can detect plastic gas pipes

　　K. will be evaluated

　　L. uses gas and electricity

　　M. is likely to make it easier to locate the lines

　　Q1. Utility companies...

　　通过快速浏览，我们找到了原句：Utility companies, construction projects, and highway contractors are often faced with the need to excavate or pipe-jack in the vicinity of known or suspected buried utility lines, drains, or other subsurface structures.

　　根据这一句的意思，我们发现选项Doften need to dig holes near some subsurface structures与原文的意思相符。这是因为，我们可以从原句中找到 need, excavate, in the vicinity of , subsurface structures。这几个词事实上就是这个句子的主干部分，并且这也与备选句的意思相同，因此应该选D。而选项A虽然也合乎情理，但在文中没有出现，所以只是干扰项，不能选作答案。

　　Q2.Trial pits...

　　同样，我们发现原句是：One way to verify the location of such buried objects is to cautiously dig a trial pit to expose the object in question.

　　读完Trial pits所在的这个句子，我们发现选项B与F都与原句的意思相近。那到底应该选哪一个呢?通过分析可以发现，dig trial pits 的目的并不是 expose the object，而是 verify the location of the buried objects。因此，F才是正确的选项。

　　Q3. Mechanical digging equipment...

　　原句：Where mechanical digging equipment is used, an undocumented or misaligned utility line can be easily be damaged if it is not observed by the excavation workers. Gas and electricity lines present very obvious safety threats in this situation.

　　从Mechanical digging equipment所在的句子我们可以看到这样几个词：undocumented, utility line, easily be damaged.。把这几个词连成句子后恰好和备选项Cdamages easily undocumented utility lines意思一样。但能否就贸然选C呢?仔细阅读原句可以发现，damage easily the undocumented utility line 是在没有被 excavation workers 发现的情况下，因此可以说是受这一条件限定。如果选C，就以偏概全，把特定情况下发生的问题说成了总的经常性的问题。自然，C不能选择。

　　Q4. Geophysical survey method...

　　原句：There are several geophysical techniques with proven capabilities in non-intrusive subsurface investigation....

　　The real driving force behind the development of geophysical survey methods was the search for oil and other valuable mineral deposits.

　　做这个题时，首先要细心，不要把 geophysical techniques 和geophysical survey methods混淆起来，要准确找到需要的词语。在原文句子中，我们看到象 development, search for, oil, valuable mineral deposits这样的词，它们的意思与备选句are developed to search valuable mineral deposits几乎是完全相同，因此，答案应当是E。

　　Q5.GPR...

　　原句：a. Where soil conditions are appropriate, GPR can provide the most complete and accurate information about buried structures and utility lines, but requires a carefully laid out survey grid or pattern if....

　　b. GPR will detect non-magnetic or non-conductive lines such as plastic gas pipes.

　　该题同第三题，应注意 where soil conditions are appropriate属于限定性条件，因此不能选H选项。

　　Q6. EM conductivity survey...

　　原句：EM conductivity surveys will be much more economical than GPR, but will provide little or no useful depth information.

　　在EM conductivity survey 所在的句子中有provide little or no useful depth information 这样的词句，这与选项中provides little useful depth information几乎一样，因此，答案应该为G。

　　Q7. The development of a magnetic plastic gas pipe...

　　原句：A magnetic plastic gas pipe has been developed under the auspices of the Gas Research Institute, and is currently being evaluated under field conditions. If the durability of the material lives up to expectations, and the cost becomes competitive with current gas line products, location of the new lines will be greatly simplified....

　　在这道题中，我们看到，The development of a magnetic plastic gas pipe 所在的句子中没有与选项意思相近或相符的词句，而这个句子又是唯一的一个含有该短语的句子。这时候，我们就要继续看下一个句子，看这个句子逐渐展开后的意思。果然，我们看到有location of the new lines will be greatly simplified，与选项is likely to make it easier to locate the lines意义相符。这样答案就找到了。