5 Error Identification Traps in TOEFL ITP (Written Expression Questions 16-40)
TOEFL ITP error identification: the 5 most common traps in Written Expression questions 16-40, with example sentences, how to spot the wrong word, and a quiz.
Ever read a Written Expression sentence three times and thought, “Wait, everything looks correct”? Then you’ve met the most classic TOEFL® ITP trap: a sentence that sounds fine but hides one grammatically wrong word.
In TOEFL ITP, Section 2 (Structure & Written Expression) has 40 questions in 25 minutes. Questions 1-15 are Structure (complete the sentence), while questions 16-40 are Written Expression: four parts of a sentence are underlined (A, B, C, D), and your job is to find the one that is wrong. That’s why this part is often called error identification.
The good news: the errors test writers plant follow repeating patterns. Here are the 5 traps that slip past readers most often. (The slides below are in Indonesian, with the English example sentences.)
Why “It Sounds Right” Isn’t Enough
Written Expression is designed to fool people who judge sentences by how natural they sound. The sentences are long and academic, and the errors are tiny: one letter -s, one word ending, or one unnecessary word.
So don’t read and guess. Check every underlined part against a clear checklist. The five traps below can be that checklist.
Trap 1: Subject Separated from the Verb
Test writers like to insert a long prepositional phrase (of…, in…, on…, with…) between the subject and the verb. As a result, the word right before the verb is not the real subject.
❌ The effects of pollution on sea life is critical.
✅ The effects of pollution on sea life are critical.
Cross out the middle: of pollution on sea life. What’s left is The effects … are critical. The subject is effects (plural), so the verb must be plural.
Another common example:
❌ The list of required books are posted online.
✅ The list of required books is posted online.
This time it’s the reverse: the subject is list (singular), not books.
Quick method: whenever a verb is underlined, find the main subject first and ignore every prepositional phrase in between. For a refresher on singular and plural subjects, see the singular vs plural guide.
Trap 2: Wrong Part of Speech
This is the most frequent trap. The test puts a word with the right root but the wrong word class: a verb where a noun belongs, an adjective where an adverb belongs, and so on.
❌ The team made a significant discover yesterday.
✅ The team made a significant discovery yesterday.
After the adjective significant, the sentence needs a noun. Discover is a verb, so the correct form is discovery.
Position patterns to memorize:
- Adjective + Noun: rapid growth, a significant discovery
- Adverb + Adjective: extremely important, highly effective
- Verb + Adverb: grow rapidly, work carefully
❌ The results were extreme important.
✅ The results were extremely important.
An adjective like important is modified by an adverb, not another adjective. For the basics of word classes, read Parts of Speech 101.
Trap 3: Much vs Many
Quantifiers must match the type of noun:
- Many / few / a number of for countable plural nouns: books, dollars, days, students
- Much / little / an amount of for uncountable nouns: money, research, information, equipment, time
❌ The course has too much assignments to finish.
✅ The course has too many assignments to finish.
Assignments is a countable plural, so it needs many.
Watch for the reverse too. Words like research, information, equipment, and advice don’t take a plural -s and aren’t used with many:
❌ The professor has done many researches on this topic.
✅ The professor has done much research on this topic.
Note: a final -s is a strong clue, not an absolute rule. Some uncountable nouns end in -s, such as news, physics, and economics, and they still take much and a singular verb (The news is…).
Trap 4: Another vs Other
Another comes from an + other, so it only goes with a singular countable noun. For plural nouns, use other.
❌ She collaborated with another researchers on the study.
✅ She collaborated with other researchers on the study.
In short:
- another + singular noun: another student, another theory
- other + plural noun: other students, other theories
- the other + singular or plural noun (the remaining or specific one/ones): the other book, the other books
When you see another followed by a plural noun ending in -s, that’s almost certainly the error. A minor exception: another can come before a number + plural noun treated as one unit, as in another two weeks. This is rarely used as a trap.
Trap 5: Redundancy
Academic English values concise sentences. If two words carry the same meaning, one of them is redundant and counts as an error.
❌ The lab team will repeat the experiment again tomorrow.
✅ The lab team will repeat the experiment tomorrow.
Repeat already means “do again”, so again is redundant. Other redundant pairs that often appear:
| ❌ Redundant | ✅ Enough |
|---|---|
| repeat again | repeat |
| return back | return |
| advance forward | advance |
| revert back | revert |
| new innovation | innovation |
| the reason is because | the reason is that |
In the test, the redundant part is usually a small word like again, back, or forward that is also underlined.
Summary of the 5 Traps
| No | Trap | What it looks like | How to check |
|---|---|---|---|
| 1 | Separated subject | A long of/in/on phrase before the verb | Cross out the middle, match the verb to the main subject |
| 2 | Wrong part of speech | Right root, wrong ending | Look at the words before and after |
| 3 | Much vs many | Quantifier + noun | Countable plural = many, uncountable = much |
| 4 | Another vs other | another + plural noun | Another = singular, other = plural |
| 5 | Redundancy | again, back, forward after a verb with the same meaning | Delete the word that repeats the meaning |
Quick Quiz
Find the wrong word in each sentence:
- The number of students in the classes have increased this year.
- Many information about the project is available online.
- The museum plans to open another galleries next spring.
- The rapid develop of the city surprised many planners.
Answers:
- have → has. The main subject is the number (singular); of students in the classes is just a modifying phrase.
- Many → Much. Information is uncountable.
- another → other (or another gallery). Galleries is plural.
- develop → development. The adjective rapid needs a noun after it.
Practice Written Expression Until It’s Automatic
Understanding these five patterns is step one. To spot errors in seconds, you need plenty of practice with TOEFL-style sentences.
Kawan EPT (formerly Kawan TOEFL) has 7,400+ questions with explanations for every answer choice, Grammar lessons on 33 topics with Learn, Drill, Master stages, a full 140-question simulation with a score estimate from 310 to 677, and a Weakness Drill that targets the topics you miss most. Free on the Google Play Store.
Just getting started? Read the complete TOEFL ITP guide.