IELTS Reading lesson 3: Sentence Completion

There are questions on IELTS Reading that ask you to fill in the gaps in the sentences. Those gaps should be filled with words taken directly from the reading text. And you are given a word limit, for example: "Write NO MORE THAN TWO WORDS ..."

This type of questions is called sentence completion and may look like this on the question paper:

Complete the sentences below.

Write NO MORE THAN THREE WORDS from the passage for each answer.

Write your answers in boxes 28–30 on your answer sheet.

 

28. Nowadays, scientists consider atoms’ structures similar to tiny ................................. .


Useful information about sentence completion questions:

So you are given sentences, which you have to complete. Those sentences are not exactly taken from the text: they are paraphrased. But they keep the initial meaning.

Key words from questions may be your pointers: they'll help you to find the passage that contains the answer. But to find the answer, you should understand the meaning of the question and find the sentence with the same meaning in the text. So you should look for meaning, not separate words.

Note that if you are asked to complete sentence with no more than two words, you can write one or two words.

To understand the theory better, see an example below.


Answering strategy:

  1. Read the text.
  2. Use key words to find the needed paragraph.
  3. Make sure you understand the question statement and search for sentence with similar meaning.
  4. Once you've found the answer, check if it fits into the statement grammatically and doesn't exceed the word limit.
  5. Repeat this strategy with other questions.

    6. If you prefer, you can read the text by passages.


Tips:

Sentence completion exercises with detailed explanations:


Example:

How atoms were discovered

Hundreds of years ago in 1785 Dutch scientist Jan Ingenhousz was studying a strange phenomenon that he couldn’t quite make sense of. Minute particles of coal dust were darting about on the surface of some alcohol in his lab.

About 50 years later, in 1827, the Scottish botanist Robert Brown described something curiously similar. He had his microscope trained on some pollen grains. Brown noticed that some of the grains released tiny particles – which would then move away from the pollen grain in a random jittery dance.
At first, Brown wondered if the particles were really some sort of unknown organism. He repeated the experiment with other substances like rock dust, which he knew wasn’t alive, and saw the same strange motion again.

It would take almost another century for science to offer an explanation. Einstein came along and developed a mathematical formula that would predict this very particular type of movement – by then called Brownian motion, after Robert Brown.

Einstein’s theory was that that the particles from the pollen grains were being moved around because they were constantly crashing into millions of tinier molecules of water – molecules that were made of atoms.

By 1908, observations backed with calculations had confirmed that atoms were real. Within about a decade, physicists would be able to go further. By pulling apart individual atoms they began to get a sense of their internal structure.

It might come as a surprise that atoms can be broken down – particularly since the very name atom derives from a Greek term “atomos”, which means “indivisible”. But physicists now know that atoms are not solid little balls. It’s better to think of them as tiny electrical, “planetary” systems. They’re typically made up of three main parts: protons, neutrons and electrons. Think of the protons and neutrons as together forming a “sun”, or nucleus, at the centre of the system. The electrons orbit this nucleus, like planets.

Sentence completion questions:

  1. The type of random jittery movement of tiny particles is called .......................... .

    The key words here are type of movement, and they direst us to the third paragraph. There, we can see a phrase with the same meaning:

    this very particular type of movement – by then called Brownian motion

    It refers to the movement of tiny particles described in the first two paragraphs.

    So the answer is Brownian motion.

    Note how the new term from the text is used for sentence completion. This is quite common for sentence completion questions in IELTS Reading.


  2. Einstein explained the phenomenon of particles' strange motion by the fact that they were collapsing with .......................... .

    The key words here are Einstein explained. The fourth paragraph tells us that

    Einstein's theory was that that the particles from the pollen grains were being moved around because they were constantly crashing into millions of tinier molecules of water

    Look how the synonyms are used:

    • Einstein's theory = Einstein explained
    • crashing into = collapsing with

    Now we see that the correct answer is water molecules.

    But why not "molecules of water" as it was stated in the text? Because the question asked to complete the sentences with NO MORE THAN TWO words, so three-word answer is automatically incorrect. That's why here we had to rephrase the correct answer to make it fit into the word number boundaries. You should always pay attention to this!


  3. Nowadays, scientists consider atoms' structures similar to tiny .......................... .

    Atoms' structures are discussed in the last paragraph, where we can find a paraphrase of our question statement:

    But physicists now know that atoms are not solid little balls. It's better to think of them as tiny electrical, "planetary" systems.

    • Scientists = physicists
    • Nowadays = now
    • Consider = think of them as

    Correct answer: planetary systems.


  4. .......................... are parts that are circling around the nucleus.

    Again, nucleus was introduced only in the last paragraph, so we should search for the answer there. The last sentence of the last paragraph states that

    The electrons orbit this nucleus, like planets.

    Knowing that circle around = orbit, the correct answer is obvious: electrons.


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