toefl guide

TOEFL Reading Question Type - Rhetorical Purpose Question

Madison Oster October 12th, 2021

This is part of a series of TOEFL Reading Question Types. In today’s post, we will discuss a "Purpose" question. This type of question requires you to understand why the author has included a piece of information. Because the answer to this question is not directly stated in the reading passage, you need to understand the main point of the paragraph and how the referenced information is related to the main point of the paragraph in order to solve this type of question.

A purpose question is often phrased like the following:

Why does the author mention (X)?The author mentions (X) in order to…The author includes the information of (X) in order to…The author uses (X) as an example of…The author mentions (X) for which of the following reasons?The author does (X) in order to…What is the author’s purpose in mentioning…

You will also see answers that contain phrases like the following

to show/to illustrateto account for/to explainto support/to refute/to opposeto criticize/to questionto contrast/to compare

Let’s look at an example of a purpose question.

TOEFL Reading Practice: Purpose Question

[4]  Darwin's theory is that 'selective breeding' occurs in nature as 'natural selection' is the engine behind evolution. Thus, the theory provides an excellent basis for understanding how organisms change over time. Nevertheless, it is just a theory and elusively difficult to prove. One of the major holes in Darwin's theory revolves around “irreducibly complex systems.” An irreducibly complex system is known as a system where many different parts must all operate together. As a result, in the absence of one, the system as a whole collapses. Consequently, as modern technology improves, science can identify these “irreducibly complex systems” even at microscopic levels. These complex systems, if so inter-reliant, would be resistant to Darwin's supposition of how evolution occurs. As Darwin himself admitted, “To suppose that the eye with all its inimitable contrivances for adjusting the focus for different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I free confess, absurd in the highest degree.

Question: In paragraph 4, what was the author's purpose of including a quote that the belief that the complexity of the human eye could have been formed by natural selection seems highly unlikely?

  1. To provide evidence that irreducibly complex systems exist
  2. The proof that the natural selection contradicts the basis of Darwin
  3. The support that the natural selection contributes to the basis of Darwin
  4. The support the claim that natural selection is just a theory and difficult to prove
D is the correct answer. The quote shows that even Darwin, who created the theory, acknowledges that some of the occurrences are difficult to believe and difficult to prove. A is incorrect because the quote is not providing information that would prove the existence of irreducibly complex systems. B and C are incorrect because the quote does not say whether the idea of natural selection contributes to or contradicts the theory.

TOEFL Reading Tips & Strategies: How to Answer “Purpose” Questions

These questions require more than just English skills. They require critical thinking.  Your job is to try to determine why the author included this information.  Here are 5 tips for answering a purpose question:

  1. Read the question carefully and understand what you are being asked
  2. Make sure you understand the whole paragraph. 
  3. Look for transition words. These often are a huge clue to why the author included certain information.
  4. Consider the big picture of the paragraph.  Usually, the question is related to the big picture of what the paragraph is trying to present. 
  5. Use the process of elimination. Answers are often incorrect if they are too extreme (words like none, never, forever, always, etc.), if they are not mentioned, or if they are untrue according to information in the paragraph.


If you want to practice more TOEFL reading purpose questions, sign up for our TOEFL preparation course to access our 72 complete TOEFL reading practices and 13 extra purpose questions in our TOEFL reading lessons.

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