Line graphs and the language of trends

Read the graph before you describe it

After the two-minute analysis from Lesson 2, mark the key points of each line:

• the start and end values, plus any projected values
• the highest point (peak) and lowest point (low or trough), with years
• turning points, where the direction changes
• crossings, where one line overtakes another
• sections that are flat or fluctuating

On the electricity graph:

• Gas starts at 12, climbs to a peak of 45 in 2020, then flattens and is projected to fall slightly.
• Oil peaks early (14 in 2010), then declines steadily.
• Coal is almost flat until 2015, then jumps.
• Solar is close to zero until 2015, then soars, and is projected to overtake coal by 2030.

Those key points are all you need. Points that simply continue a trend, such as gas in 2005, can usually be left out. Selecting is what the task asks you to do.

Collocation traps

• Contradictions: soared slightly, plummeted gradually, a dramatic plateau. Soar and plummet already mean ‘large and fast’, so they need no adverb at all.
• Wrong intensifiers: increased highly, decreased hugely, a strong rise, a big increase. Use increased significantly, a sharp rise, a substantial increase.
• Adjective vs adverb: the adjective goes with a noun (a sharp rise); the adverb goes with a verb (rose sharply). Rose sharp and a sharply rise are grammar errors.
• Size vs speed: rapid describes speed, significant describes size. A line can rise significantly over 30 years without rising rapidly.

Five ways to describe one trend

Solar output, 2015–2025: from 2 TWh to 14 TWh.

1. Subject + verb + adverb: Solar output rose sharply between 2015 and 2025.
2. There was + adjective + noun + in: There was a sharp rise in solar output between 2015 and 2025.
3. Time period as subject + saw: The decade from 2015 to 2025 saw a sharp rise in solar output.
4. Subject + experienced / recorded + noun: Solar power experienced a sevenfold increase over the decade.
5. Main clause + -ing clause with the figures: Solar output rose sharply, climbing from 2 TWh in 2015 to 14 TWh in 2025.

Patterns 1 and 5 are the most natural; use 2–4 occasionally for variety. Witnessed (as in the decade witnessed a rise) is common in IELTS answers, but saw sounds more natural.

Tense rules that prevent errors

• Never use the present simple for past data. In 2010, oil peaks at 14 TWh is wrong; write peaked.
• Never use the present perfect with a finished time. Oil has peaked in 2010 is wrong; write peaked in 2010. Use the present perfect only with since or over the past …, and only when the data reach the present.
• Don’t present projections as facts. Solar reached 30 TWh in 2030 is wrong. Use is expected / projected / predicted / forecast to reach. Vary the verb across the answer.

Grouping the lines

With three to five lines, never describe each one from start to finish in turn without comparing them. Group them:

• by direction: the lines that rose vs the lines that fell;
• by shape: the lines that peaked and declined vs the lines that grew late;
• by size: the main line vs the minor ones;
• by phase: before vs after a turning point (for example, before and after 2015).

For the electricity graph, the clearest split is gas and oil (traditional sources that rose, peaked and are now falling) vs coal and solar (small at first, with late growth). Within each paragraph you can now compare: Oil followed a similar but earlier pattern…

Choosing figures and approximating

For each line, report its start, its peak or low (with the year), any turning point, and its end or projection: usually 4–6 figures per paragraph. When the value falls between gridlines, approximate honestly:

• just over / just under / around / approximately / roughly / nearly / almost
• fractions for percentages: a quarter, roughly a third, almost half, two thirds, the vast majority
• multiples: doubled, more than tripled, a sevenfold increase, twice as much as