Wrong preposition – https://www.grammarbook.com/grammar/probPrep.asp
Different word classes
Subject verb agreement
Negative prefixes
Articles – a, an, the
Have you ever attempted an editing practice or examination question where you thought there was some error in a line but couldn’t quite pin it down? Here are some common errors you can look out for in your next editing exercise.

1.Negative prefixes

Negative prefixes like un-, in-, de-, dis-, or mis- all invert root meanings, but there are subtle differences from word to word.

Take this pair of words “unsatisfied” and “dissatisfied” for example.

Unsatisfied: less than 100% contented

E.g. That was an unsatisfying meal as there was not enough food for me.

Dissatisfied: completely not satisfied, bordering on annoyance

E.g. She was dissatisfied with the way the oysters were served at the restaurant.

Another example is the pair “uninterested” and “disinterested”.

Uninterested: less than fully interested in something

E.g. The children looked uninterested when the teacher was explaining the rules.


a) being impartial (unbiased; neutral)
E.g. Jeremy was allowed to take part in the discussion as he was a disinterested party.

b) Showing indifference (lack of interest)
E.g. It is troubling to learn of teenagers’ disinterest in political issues.

In both cases, there is a significant difference in meaning depending on whether the prefix ‘un’ or ‘dis’ is used. For more examples, you can check out this link.

2. Different word classes

Another common error is the use of incorrect word classes. For example, an adjective is used in place of an adverb, or a verb is used in place of a noun or an adjective.

An example may make this clearer:

He thoughtful collected her homework for her as she was sick.

The error here is in the adjective “thoughtful”, which should instead be an adverb, “thoughtfully” to describe the verb (“collected”) behind it.

This is the correct sentence:

He thoughtfully collected her homework for her as she was sick.

3. Wrong prepositions

One of the most popular errors found in editing exercises has to do with prepositions – or rather, the use of incorrect ones. Prepositions indicate relationships between nouns or pronouns and other words in the sentence. Prepositions are commonly used to indicate the location (at, on, above, in between…) or when something happened (before, after, since…).

Let’s look at an example of an incorrect preposition:

I sent the letter at my friend.

The error in this sentence is the preposition “at”, it should be replaced with “to”:

I sent the letter to my friend.

Because there are so many prepositions to remember, it helps to start with a few common prepositional phrases. Here is a website where you can find explanations of prepositions and their accompanying examples. A quick Google search for “examples of prepositional phrases” will also turn up many images and charts that you can print out to help you remember them.

4. Articles – a, an, the

Definite vs. Indefinite articles

The only definite article is “the”, which is used when referring to a specific person, object or phenomenon.

E.g. “The baby in the train was crying.”

Indefinite articles include “a” and “an”, which are used when referring to any person, object or phenomenon that cannot be identified specifically.

E.g. “I could hear a baby crying in the vicinity.”

The article “an” is used before a noun/adjective that begins with a vowel sound (sounds created by words starting with the letter “a”, “e”, “i”, “o”, “u” and sometimes ‘y’ if it makes an ‘e’ or ‘i’ sound.)

E.g. “An ear-splitting cry of a baby pierced through the silence.”

For more examples, check out this link.

5. Subject-verb agreement

Another grammatical error you might have heard your English teachers mention is that of subject-verb agreement. As a rule, a singular subject (he, Tom, dog) takes a singular verb (is, runs, barks), whereas a plural subject takes a plural verb.

In addition, the word “of” (e.g. a basket of fruits) tends to confuse many students as the subject in this sentence is the basket (singular), and not the fruits (plural).

Here’s an example:

The basket of fruits brighten up the dreary room.

The correct sentence is:

The basket of fruits brightens up the dreary room.

For more examples, check out this link.