IELTS Reading · Ch 14

Diagram Label Completion

Spatial vocabulary · technical noun phrases

Topic & Why It Matters

Diagram Label Completion appears when a passage describes something visual: a machine, a natural structure, a building layout, or a technical process. The question asks you to complete labels on a diagram using words from the passage.

Learners often lose marks because they treat the diagram like ordinary sentence completion. In this question type, position matters. A correct answer must fit the grammar of the label, obey the word limit, and match the exact part indicated by the arrow or bracket.

Knowledge Points

What Diagram Label Completion tests
Diagram Label Completion asks you to name parts of a process, machine, building, natural feature, or biological structure. It tests whether you can connect visual position with exact passage wording.
The diagram is a map of relationships
Labels are not random vocabulary blanks. Their arrows, brackets, and positions show relationships: inside/outside, upper/lower, inlet/outlet, source/result, or before/after. Reading the diagram first gives you a search plan.
Spatial vocabulary controls location
Words such as above, beneath, outer, inner, central, adjacent, at the base, and on either side often point directly to the answer. Circle these words in the passage because they link text descriptions to visual labels.
Technical noun phrases must be copied exactly
Most answers are noun phrases: filter layer, pressure valve, storage chamber, root membrane. Do not invent a simpler word if the passage gives a precise technical term.
The word limit is strict
If the instruction says NO MORE THAN TWO WORDS, an answer such as 'the upper glass panel' is wrong even if the idea is correct. Remove articles unless they are necessary and copy only the required phrase.
Order may follow the diagram, not the passage
Unlike sentence completion, diagram labels can move around a visual. The passage may describe a structure from outside to inside, while the question numbers may move top to bottom or left to right.

Step-by-Step Strategy

1
Read the diagram title and label positions
Identify what the diagram shows. Notice whether labels point to parts, materials, flows, or directions.
2
Predict the grammar of each blank
Use the words beside each blank to decide whether you need a material, a container, a device, a layer, or a process noun.
3
Scan for visual anchors
Look in the passage for nouns already printed on the diagram and for spatial signals such as upper, lower, inside, beneath, inlet, outlet, and base.
4
Read the full description window
Once you find a likely anchor, read one or two sentences around it. The answer is usually near the anchor, but a nearby noun can still be the wrong part.
5
Copy only the label phrase
Write the exact words from the passage that name the labelled part. Avoid adding articles, adjectives, or explanations that exceed the word limit.
6
Check the completed diagram spatially
After answering, trace each arrow or bracket again. The label should make sense in that exact physical position.

Common Pitfalls

MistakeCorrective Rule
Ignoring arrows and bracketsThe pointer tells you which part is being labelled. Read the diagram like an object, not like a list of blanks.
Choosing a general noun instead of the technical termIf the passage says 'condensation plate', do not write 'plate' unless the blank only asks for one word and the full phrase is impossible.
Copying a noun from the same sentence but the wrong positionCheck the spatial signal. A sentence can mention an upper cover, side vents, and a lower tray; only one matches the arrow.
Letting prior knowledge override the textIELTS labels are marked from the passage, not from what a real device normally contains. Use passage wording only.
Forgetting singular and plural formCopy the noun number exactly when it matters. 'Vents' and 'vent' may refer to different labelled features.

Vocabulary & Signpost Bank

Expression / SignalWhat It Means for Your Strategy
above / below / beneathVertical position; useful for top and bottom labels
outer / inner / centralLayer or container relationships
at the base / on the roofFixed structural locations
adjacent to / beside / on either sideLabels near neighbouring parts
inlet / outlet / ventOpenings where air, water, or material enters or leaves
is attached to / is fitted withA smaller component connected to a larger structure
lined with / covered bySurface material or protective layer
chamber / reservoir / trayContainers that hold liquid, air, or collected material

Practice Passage & Questions

Read the passage, then complete the diagram labels below. Click Check Answers to see model answers with exact passage references.

A Passive Solar Still~380 words
A

In regions where electricity is unreliable, engineers have developed a passive solar still that can produce small quantities of drinking water without pumps or batteries. The device is built inside a shallow insulated box, whose dark interior absorbs heat from sunlight. A transparent glass cover is fixed above the box at a slight angle, allowing sunlight to enter while also forming the surface on which clean water later condenses.

B

Before operation begins, untreated water is poured into a broad evaporation tray at the base of the box. The tray is painted black so that it warms quickly during the day. Around the tray, a thin rubber seal prevents vapour from escaping through the sides. This seal is important because even small leaks reduce the amount of water that can be collected.

C

As the tray heats up, water evaporates and rises toward the cooler underside of the glass cover. Dust, salt, and most microorganisms remain in the tray because they do not evaporate with the water. When the warm vapour touches the glass, it forms tiny droplets. These droplets run down the sloping surface into a narrow collection channel attached to the lower edge of the cover.

D

The collection channel leads to an external storage bottle through a short outlet tube. To stop insects and dust from entering the system, the tube is fitted with a removable mesh screen. Some versions of the still also include side vents with small shutters, which can be opened briefly after use to release excess heat and moisture.

E

Although a solar still cannot provide enough water for a large household, it is useful for emergency kits, field research stations, and remote clinics. Its main advantage is simplicity: regular cleaning of the tray, glass cover, and mesh screen is usually the only maintenance required. Because all key parts are visible, users can also identify damage without specialist tools.

Diagram: Passive Solar Still

1
2
3
4
5
6
7
  1. Angled transparent __________
  2. Black __________ at the base
  3. Rubber __________ around the tray
  4. Droplets flow into the __________
  5. Short __________ to external bottle
  6. Removable __________ blocks insects and dust
  7. Side __________ release excess heat

Questions 1-7. Complete the diagram below.

Choose NO MORE THAN TWO WORDS from the passage for each answer unless a question states ONE WORD ONLY.

1.Angled transparent __________
Answer:
2.Black __________ at the base
Answer:
3.Rubber __________ around the tray
Answer:
4.Droplets flow into the __________
Answer:
5.Short __________ to external bottle
Answer:
6.Removable __________ blocks insects and dust
Answer:
7.Side __________ release excess heat
Answer:

Self-Check

Answer these from memory. If you cannot answer all three, re-read the relevant section.

  1. What visual features should you inspect before reading the passage?
  2. Why are spatial words such as above, beneath, outer, and at the base useful?
  3. How do you avoid choosing a nearby but incorrect technical noun?
Answers:
  1. (1) Inspect the title, arrows, brackets, label positions, printed nouns, and any direction of flow. These features tell you what kind of phrase each blank needs.
  2. (2) Spatial words connect the passage description to the diagram. They tell you whether the answer belongs to a top, bottom, side, inner, outer, or adjacent part.
  3. (3) Read the full sentence window and match the noun to the arrow position and grammar of the blank. Then copy only the exact phrase that names the labelled part.