Day Four A类小作文（四）
对比示意图和组合图
对比示意图是流程图的一种变体。它们之间的区别在于：一般的流程图侧重于多个步骤之后所产生的结果（比如一个工业生产过程中所形成的产品），而对比示意图则更注重几个不同阶段（通常是2～4个）之间的差异比较。
与普通流程图相比，对比示意图要求雅思考生更具备对物体形状、大小、体积（容积）及功用等方面的描写能力。
请看下面一道经典的对比示意图：
整个图中的cooking equipment从最简单的Stage A一直发展到较为复杂的Stage C。从分段的角度来说，可以考虑把Stage A和Stage B放在主体段一描写，把内容较多的Stage C放到主体段二里面去写。
【原创范例】
In Stage A, the cooking vessel is in the shape of a large vase, under which there are several stones to hold some firewood that heats the food inside the vase.The fact that this tall container has a narrow mouth makes it extremely difficult to put in and take out food.This problem is successfully solved in Stage B, where the much shorter cooking vessel is formed essentially by a circle of clay shield with a wide mouth as well as a side opening.Firewood is both put at its bottom and inserted from the opening, while some sizable stones are placed within the shield.
下面的主体段二围绕最复杂的Stage C来展开：
【原创范例】
The cooking equipment becomes far more complicated in Stage C as it is made up of two parts. As a matter of fact, the lower part is a modification of the clay shield in the previous stage.While the shield consists of a round and of metal instead of clay, the original side opening is now replaced by a rectangular vent with a sliding door to let charcoal and air in and take ash out.The higher part is a metal container with clay lining as some sort of insulation.We can use the handle at the side to hold the container in place, and there are three triangular pieces of metal to support a pot.The bottom of the container is in fact a grate to allow charcoal to be burnt.
综合两个段落来看，其中有三个表示“由……组成/构成”的表达方式：
be formed essentially by……
be made up of……
consist of……
另外还有不少动词不定式，来表达事物的功能或目的：
to hold some firewood that heats the food inside the vase
to put in and take out food
to let charcoal and air in and take ash out
to hold the container in place
to support a pot
to allow charcoal to be burnt
归纳起来，对比示意图有以下三大要领需要掌握：
1.具备“看图识字”的能力，根据图形写出文字。
2.具备对物体的形状及功能的描写能力，使用恰当的形容词和名词。
3.具备运用动词被动语态及动词不定式的能力，来描述事物的构造及功能。
对比示意图练习
对比示意图小贴士
与流程图相似的是，对比示意图（profile diagram）也是一种基本没有数据的图形。它的主要考查点在于检验考生对两个相对的事物或一个事物两个相对的方面进行描述的能力。历年出现过的考题既有要求对洪水灾区的两种解决方法优缺点的描述，也有对超市两个选址的各自利弊的描写等。
对付这类题型的关键是必须要掌握“优缺点”的多样表达，以及对比关系连词的灵活使用。现举例句型如下：
……is a far better solution than……because……
In comparison，……seems to have more……than……
Compared with……，……offers greater convenience in that……
All in all, the advantages of……far outweigh its disadvantages.
如果对比示意图展示的是两件产品或两个物件，那么我们可以从以下的五个层面进行逐一描写：
1.形状与轮廓（form and shape）
2.材料与部件（material and component）
3.尺寸与容积（size and volume）
4.连接与通道（connection and channel）
5.比较与对照（comparison and contrast）
掌握这五大原则，任何物品的对比示意图都可以按部就班、有条不紊地描写出来。
组合图之所以成为一种较难的复杂图表，就在于它是由若干个（一般为2～3个）简单图表组合而成。这些简单图表包括我们之前分析的曲线图、柱状图、饼形图和表格图。既然出现在一道题目里面，这2～3个简单图表一定是关于同一个主题的，而且有可能存在某些密切的联系。
请看下面一个由流程图加饼形图所构成的组合图：
原题是这样写的：The diagrams show how chocolate is made and how the price of a chocolate bar is divided up among those involved in the process.
Summarise the information by choosing and reporting the key features, and make comparisons where relevant.
首先我们必须了解，组合图的主体段就是按照图表的类型来进行分段的，因此针对上面的组合图，我们的主体段一应该描述上面的流程图，主体段二来分析下面的饼形图。
在流程图中，从一开始的cocoa grinding到最后的chocolate bar，这条主线的步骤一共有四个。副线有两条：一是由cocoa grinding产生了waste；二是对cocoa liquor进行挤压（pressing），变成cocoa butter和cocoa powder，而cocoa powder最终进入了food industry。
【原创范例】
First of all, a large quantity of cocoa beans are ground to make cocoa liquor, although some waste is also produced.In the second stage, while the majority of the cocoa liquor is turned into industrial chocolate, a considerable portion of it is being pressed to become both cocoa butter and cocoa powder.On the one hand, cocoa powder is delivered to the food industry as an essential foodstuff.On the other hand, industrial chocolate is mixed with cocoa butter as well as sugar and other ingredients.It is only in this way that the final product of chocolate bar can be created.
这段是对流程图的写作，因此在写每一个步骤的时候，我们必须加入一些动词来构成完整的句子，而且在很多情况下，动词的被动语态更经常出现在流程图的作文中。下列为该段中所有的动词表达方式：
are ground to make……
is also produced
is turned into……
is being pressed to become……
is delivered to……
is mixed with……
can be created
在引出每一个步骤时，该段运用了大量的信号词：
first of all
in the second stage
on the one hand
on the other hand
it is only in this way that……
另外，该段也使用了不少量词来修饰名词：
a large quantity of
the majority of
a considerable portion of
在饼图中，一共有五块百分比构成。为了避免“报流水账”，我们可以先将最大的一块（37%）单独写，然后把反差较大的34%和4%放在一起进行对比，最后把数值接近的10%和15%归入一句话中描写。
【原创范例】
When it comes to how different parties divide the price of a chocolate bar, the cost of ingredients and overheads take the lion’s share（37%）.While supermarkets account for a little more than one third of the price, only a small fraction（4%）goes to the farmers.In comparison with chocolate companies that represent 10%of the total price, taxes for chocolate bars constitute 15%.
该段采用了一些地道的句型：
When it comes to……，……
While……，……
In comparison with……，……
由于整个段落是在分析百分比，因此出现了大量表示“占……比例”的用语：
take the lion's share（占最大的份额）
account for
represent
constitute
而在讲farmers所占的比例时，用了极为简单、却非常有效的动词词组：
only a small fraction（4%）goes to……
由此可见，在雅思写作中，无论用高难词还是用简单的表达方式，同样都可以获得理想的成绩，关键在于用词一定要灵活，千万不能死守在一两个单词或用语上，变化和变通才是写作的硬道理。
组合图练习
A.
B.
组合图范文
The chart compares average figures for temperature and precipitation over the course of a calendar year in Kolkata.
It is noticeable that monthly figures for precipitation in Kolkata vary considerably, whereas monthly temperatures remain relatively stable.Rainfall is highest from July to August, while temperatures are highest in April and May.
Between the months of January and May, average temperatures in Kolkata rise from their lowest point at around 20℃ to a peak of just over 30℃.Average rainfall in the city also rises over the same period, from approximately 20mm of rain in January to 100mm in May.
While temperatures stay roughly the same for the next four months, the amount of rainfall more than doubles between May and June. Figures for precipitation remain above 250mm from June to September, peaking at around 330mm in July.The final three months of the year see a dramatic fall in precipitation, to a low of about 10mm in December, and a steady drop in temperatures back to the January average.
组合图小贴士
对付组合图最好的方法还是把它看作是普通图表的一种拼凑，然后逐一描写、各个击破。当然其中的详略你可以根据图表信息量的多少自行安排。如果一边的图没有多少内容可写，我们就简略地用三言两语进行勾勒；而另一边的表格数据庞杂，那就应该对其进行挑选，并分组描写，所以主体部分的段落篇幅并不是平均的。
如果各图表之间的内在联系较为明显，或者你通过对主体段的数据分析及对比，发现了某种潜在的规律，你就可以把这种联系或规律放在结尾段去写。如果实在发现不了规律，那也没关系，可以根据自己感受最深的某一个图表做出总结陈词。
在图表与图表之间的段落过渡部分，我们经常采用如下的表达方式：
In terms of……
Turning to……
As to……
Regarding……
Then we look at……
When it comes to……
As far as……is concerned，……