概述
折线图显示在一段时间内数字的变化，所以 x 轴表示时间，y 轴表示数量。通常线条图会有3、4条线段，我们的任务是对比这些线段，而不是分开描述每一条。
- 首先进行总体上笼统的比较 (
summary/overview)
选择总体上非常一致笼统的现象，例如蓝色线条在很长的时间内都比其他的要高
- 比较特定点的线条 (
details)
选择局部的时间点，例如最开始的时间点、蓝色线和绿色线的交点及之后的发展趋势、每个线段的峰值以及长期稳定不变的时间
因为字数的限制，我们不能够描述所有的事情，因此每条线至少写一件事，并且进行相关比较。
案例
1. Introduction (对于问题进行意译)
问题：
The graph below shows electricity production (in terawatt hours) in France beteew 1980 and 2012.
问题的改述：
The line graph compares the amount of electricity produced in France
using four different sources of power over a period of 32 years.
2. Overview (2句话2个观点)
找到最明显最具概括性的 2 点进行描述。
It is clear that nuclear power was by far the most important means of electricity generation
over the period shown. Renewables provided the lowest amount of electricity in each year.
3. Details 1
可以选取开始时间点作为切入点，比较 1980 年中的 4 个数据点。还可以选取 1981 年 Nuclear 开始成为最重要的能源作为本段的内容。
In 1980, thermal power stations were the main source of electricity in France,
generating around 120 terawatt hours of power.
Nuclear and hydroelectric power stations produced just under 75 terawatt hours of electricity each,
and renewables provided a negligible amount.
Just one year later, nuclear power overtook thermal power as the primary source of electricity.
注意，这里我们在表示 Nuclear 提供了 75(TW-h) 的发电量的时候，用的是
Nuclear power stations produced 75 terawatt hours of electricity.而不能写成Nuclear produced 75 terawatt hours of electricity.我们不能只是简单的从图表中获取 Nuclear 这个词，我们需要改变它。 将
Nuclear修改为Nuclear power stations，因为是发电站在发电。或者我们还可以修改为:
Nuclear power was used to produce 75 terawatt hours of electricity.
4. Details 2
在这一段中，可以给每条线至少写一件事，找出每条线的趋势特点并比较。
Between 1980 and 2005, electricity production from nuclear power rose dramatically to
a peak of 430 terawatt hours.
By contrast, the figure for thermal power fell to only 50 terawatt hours in 1985,
and remained at this level for the rest of the period.
Hydroelectric power generation remained relatively stable, at between 50 and 80 terawatthours,
for the whole 32-year period,
but renewable electricity production saw only a small rise to approximately 25 terawatt hours by 2012.
完整范文
The line graph compares the amount of electricity produced in France
using four different sources of power over a period of 32 years.
It is clear that nuclear power was by far the most important means of electricity generation
over the period shown. Renewables provided the lowest amount of electricity in each year.
In 1980, thermal power stations were the main source of electricity in France,
generating around 120 terawatt hours of power.
Nuclear and hydroelectric power stations produced just under 75 terawatt hours of electricity each,
and renewables provided a negligible amount.
Just one year later, nuclear power overtook thermal power as the primary source of electricity.
Between 1980 and 2005, electricity production from nuclear power rose dramatically to
a peak of 430 terawatt hours.
By contrast, the figure for thermal power fell to only 50 terawatt hours in 1985,
and remained at this level for the rest of the period.
Hydroelectric power generation remained relatively stable, at between 50 and 80 terawatthours,
for the whole 32-year period,
but renewable electricity production saw only a small rise to approximately 25 terawatt hours by 2012.
好的词组
· amount of electricity produced
· sources of / provided / generating
· means of electricity generation
· over a period of / over the period shown
· by far the most important
· a negligible amount
· nuclear power overtook thermal power
· as the primary source of electricity
· rose dramatically to a peak of
· By contrast
· the figure for
· remained at this level / remained relatively stable
· remained at this level
