做matching 題目時，最重要的一點就是找到關鍵字。拿到一篇文章後，首先瀏覽文章標題，然後把題目中列出的關鍵字逐個找到，並將該詞所在的句子用線劃出。然後，我們就可以根據劃線句子的意思與問題給出的備選項進行對照，意思相近或相符的那一句就應該是正確答案。發現兩個句子意思相近或相符的關鍵是找原句中的同義詞或近義詞，這樣就可大大減少閱讀量，從而能在較短的時間內找到答案。如果答案不能在出現關鍵字的句子中找到，就應從該句的上下文中去尋找答案。還有些時候，你會發現關鍵字在好幾個句子中都出現了。這時，你可以將這幾個句子都劃出來，與備選項中的句子逐個對照，意思相近的就是正確選項。
還有一個需要注意的問題是，每選定一個答案後，應把已選好的選項用線劃掉，以免影響後面的判斷。
下面，我們就以下文為例具體進行分析。
geophysics for utility location:
when it works - when it won’t
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 author’s 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 (a-m) 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 (a-m) 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...
通過快速瀏覽，我們找到了原句：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.
根據這一句的意思，我們發現選項d‘often need to dig holes near some subsurface structures’與原文的意思相符。這是因為，我們可以從原句中找到 need, excavate(dig), in the vicinity of (near), subsurface structures。這幾個詞事實上就是這個句子的主幹部分，並且這也與備選句的意思相同，因此應該選d。而選項a雖然也合乎情理，但在文中沒有出現，所以只是干擾項，不能選作答案。
q2.trial pits...
同樣，我們發現原句是：one way to verify the location of such buried objects is to cautiously dig a trial pit to expose the object in question.
讀完‘trial pits’所在的這個句子，我們發現選項b與f都與原句的意思相近。那到底應該選哪一個呢？通過分析可以發現，dig trial pits 的目的並不是 expose the object，而是 verify the location of the buried objects。因此，f才是正確的選項。
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.
從mechanical digging equipment’所在的句子我們可以看到這樣幾個詞：undocumented, utility line, easily be damaged.。把這幾個詞連成句子後恰好和備選項c‘damages easily undocumented utility lines’意思一樣。但能否就貿然選c呢？仔細閱讀原句可以發現，damage easily the undocumented utility line 是在沒有被 excavation workers 發現的情況下，因此可以說是受這一條件限定。如果選c，就以偏概全，把特定情況下發生的問題說成了總的經常性的問題。自然，c不能選擇。
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.
做這個題時，首先要細心，不要把 'geophysical techniques' 和'geophysical survey methods'混淆起來，要準確找到需要的詞語。在原文句子中，我們看到象 development, search for, oil, valuable mineral deposits這樣的詞，它們的意思與備選句‘are developed to search valuable mineral deposits’幾乎是完全相同，因此，答案應當是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.
該題同第三題，應注意 where soil conditions are appropriate屬於限定性條件，因此不能選h選項。
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 這樣的詞句，這與選項中‘provides little useful depth information’幾乎一樣，因此，答案應該為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....
在這道題中，我們看到，‘the development of a magnetic plastic gas pipe ’所在的句子中沒有與選項意思相近或相符的詞句，而這個句子又是唯一的一個含有該短語的句子。這時候，我們就要繼續看下一個句子，看這個句子逐漸展開後的意思。果然，我們看到有location of the new lines will be greatly simplified，與選項‘is likely to make it easier to locate the lines’意義相符。這樣答案就找到了。