Communication skills resource 7: Common student grammar errors

Communication skills resource: Common grammar errors [PDF 126KB]

Comma splice error

A comma splice error occurs when two complete sentences are joined together by a comma. For example:

  • The benefits of this kind of therapy are substantial, there are relatively few adverse side effects.

Comma splice errors are quite common, particularly for native speakers of English. They often result from the desire to avoid writing short sentences. A comma splice error can be fixed in different ways, depending on the length of the sentences.

  1. If the two sentences are short, it is best to join them with a conjunction ('joining word') such as 'and', 'so', or 'but', as in the following example:
    • The benefits of this kind of therapy are substantial, and there are relatively few adverse side effects.
  2. If the two sentences are short and they are of equal grammatical weight and value, it is best to use a semicolon.
    • The benefits of this kind of therapy are substantial; the adverse side effects are relatively few.
  3. If the two sentences are already rather long, it is better to put a full stop between and have two separate sentences.
    • The reported benefits of this kind of therapy are substantial, particularly when used in conjunction with more traditional approaches. However, there are relatively few adverse side effects and these are generally not severe.

Run on sentence

Run on sentences are the same as the comma splice errors described above, except that there is no comma placed between the two sentences. These are less frequent than comma splice errors and can be fixed in the same way.

The benefits of this kind of therapy are substantial there are relatively few adverse side effects.

Sentence fragment

A fragment is an incomplete sentence. Fragments may be missing a verb or a subject or they may not convey a complete thought.

Example: A fragment that has a subject and a verb but does not express a complete thought

  • Because the lemming was heading towards the cliff. (fragment)

The above fragment contains a subject and a verb, but it does not contain a complete thought. We have the reason for something, but we don't have the 'something'. This is the most common form of fragment error. The word 'Because' at the beginning has turned a complete sentence ('The lemming was heading towards the cliff.') into a fragment, which requires another part to be a complete sentence.

To correct this sentence it needs another part. For example:

  • Because the lemming was heading towards the cliff, others decided to follow.

There are many words similar to 'because' that when used in this way, require another part to make a full sentence. Some examples are given in the table below. Don't be confused. This doesn't mean that you can't start a sentence with 'Because' (a common urban grammar myth!). You can start a sentence with 'Because' as long as you make sure to include the other part of the sentence.

  Fragment example
because Because measurements were not taken at regular intervals.
although Although the fracture was not observed.
whereas Whereas the left ear showed no sign of swelling.
since Since there were no other parameters.
unless Unless future studies find otherwise.

All of the fragments in the above table could be corrected by adding another sentence part with a subject and a verb.

Example: A fragment with no verb or subject

  • Being a very headstrong and independent lemming with a mind of her own.

This fragment does not contain a full verb or a subject. The word 'being' at the beginning of the sentence looks like a verb, but it is really only part of one. To be a full verb, an –ing word needs to be combined with a 'helping verb' such as am, is, are, was or were. (e.g. The lemming is being stubborn). To fix the fragment in the above example, another part needs to be added to make it a complete sentence.

  • Being a very headstrong and independent lemming with a mind of her own, Fifi did not join the others in their rush towards the cliff.

Here's another example of a fragment.

  • At the edge of the extremely steep cliff near a group of boulders.

The example above is a fragment because it only tells us the 'where' part of the sentence. It does not contain a subject or a verb. We don't know who is doing what. The fragment needs another part to make it a complete sentence.

  • At the edge of the extremely steep cliff near a group of boulders, the lemmings gathered for a brief, final meeting.

Subject verb agreement

In English grammar, subjects must 'agree with' verbs.  We use different forms of verbs for different types of subjects. The following table gives some examples.

subject example of subject Verb object
I (I) Like

learning grammar.

that game.

doing it.

chocolate.

You (You)
We My friends and I
They The people in the pub
He That guy in our lab Likes
She The woman in the photo
It (Even) my dog

Subject verb agreement with the verb 'to be' is a little more complicated.

subject example of subject verb (to be) complement/adverbial
I (I) Am

a great example.

extremely unreliable.

in the right place.

Intoxicated.

You (You) Are
We My friends and I
They The people in the pub
He That guy in our lab Is
She The woman in the photo
It (Even) my dog

Making subjects agree with verbs is fairly easy when the sentence is short and the subject is right next to its verb. However, when sentences are long and complex, subject verb agreement can be more difficult, as in the following example.

  • Punctuating long sentences, such as the ones in the following examples, cause difficulties for many writers.
  • Punctuating long sentences, such as the ones in the following examples causes difficulties for many writers.

In order to check whether the subject agrees with the verb, you first need to identify the main verb in the sentence ('cause' in the sentences above) and then ask who or what causes difficulties? The answer is 'punctuating'. Punctuating = 'it', so we need to use the verb form with the 's' i.e. punctuating… causes difficulties…

Errors also frequently occur when the sentence starts with 'there is/are'.

  • There is not many studies which have investigated the science of navel gazing.
  • There are not many studies which have investigated the science of navel gazing.

Problems with commas

Few people writing in English know how to use commas correctly. A lot of the time, this doesn't matter as many sentences 'requiring' a comma can be easily understood even without the comma. However, there are some instances where a sentence becomes ambiguous, or even unreadable, without a comma.

Example 1

  • I told them to eat, Lucy.
  • I told them to eat Lucy.

The difference in punctuation is small, but the difference to Lucy is considerable.

Example 2

  • When we finally packed up the instrument had already completed the scan.
  • When we finally packed up, the instrument had already completed the scan.
    (introductory bit)              (main part of sentence)

The first sentence is difficult to read because it may seem like the instrument was packed up. In the second sentence, the comma after the introductory bit makes the meaning much clearer. The introductory part of the sentence is not a full sentence on its own. If there is an introductory bit at the beginning of a sentence, it's a good habit to always place a comma between it and the main part of the sentence.

Example 3

  • In the workshop reports were made about people altering data to fit the hypothesis.
  • In the workshop, reports were made about people altering data to fit the hypothesis
    (adverbial)         (main part of sentence)

This is similar to example 2. The first sentence is difficult to read and its meaning is not clear because the words 'lab' and 'reports' are often used together as a compound noun. In the second example, a comma separates the adverbial element

Example 4

  • Recent studies on the mating behaviour of the endangered three toed sloth from South America, have analysed the frequency of the 'ay-ay' mating call.
  • Recent studies on the mating behaviour of the endangered three toed sloth from South America have analysed the frequency of the 'ay-ay' mating call.

Do not use a comma after the subject of a sentence. When the subject of a sentence is very long, you may feel that you need to put a comma between the subject and the verb. This is not correct.

Parallel structure

Problems with maintaining parallel structure often occur when constructing lists, either as dot points or within a sentence. Items in a list should be the same type of word in terms of grammar, for example, a list of nouns or a list of verbs. The following examples should illustrate.

The objectives of this review are:

  • Outlining the main conceptual areas behind the science of navel gazing
  • To give an account of the controversy surrounding the benefits of navel gazing
  • The different ways to navel gaze

Each of the dot points has a different grammatical form. To give the items in the list parallel structure, they should have the same grammatical form as in the list of verbs (actions) below.

The objectives of this review are to:

  • outline the main conceptual areas behind the science of navel gazing
  • give an account of the controversy surrounding the benefits of navel gazing
  • describe the different ways to navel gaze.

Apostrophes

Apostrophes are notoriously difficult to use correctly. There is even a website showing examples of 'apostrophe abuse' on signs from around the world. However, once you know the rules, it's really not that hard.

Points of confusion

The words that cause the most confusion when using apostrophes are it's and its.

  • It's – the apostrophe denotes a missing letter (i.e. short form of it is)
  • Its – is used to show possession but has no apostrophe (e.g. Its ears are big).

When to use them

To denote a missing letter

When we put two short words together, we use an apostrophe to show that a letter is missing. It is not common to use these shortened forms in academic writing. Here are some examples.

  1. do not /  don't
  2. is not / isn't
  3. you are / you're
  4. it is / it's
  5. we are / we're

We do not use an apostrophe to make an abbreviation or acronym (e.g. CD, USB, ATM) plural. Also, we do not use an apostrophe when making years plural. So,

CD's CDs
USB's USBs
ATM's ATMs
1960's 1960s
90's 90s

To denote possession

Apostrophes are used to show possession or ownership of something, as in the following examples. Note that the apostrophe is placed after the 's' if the noun is plural. We can also use pronouns in place of the noun. The table below contains some examples.

singular nouns pronoun plural nouns pronoun
The student's writing his/her The students' writing their
The paper's references its The papers' references their
The bee's knees its The bees' knees their
The computer's functions its The computers' functions their
Robyn's office her n/a n/a

We do not use apostrophes before an 's' in plural nouns where there is no possession.

Commonly confused words

The English language can be very confusing, so it's hard to avoid mistakes. Some commonly confused words are listed below.

word confusion explanation
effect/affect

Effect is usually a noun.

e.g. There was no effect on the reaction rate.

Affect is usually a verb (action) (remember 'a' for action & affect)

e.g. The reaction rate was not affected.

would of/would have

'Would of' is incorrect. 'Would have' is correct.

The experiment would of worked.

The experiment would have worked

few/less

Use few or fewer with 'countable' nouns.

e.g. There were few errors.

Use less with 'uncountable' nouns.

e.g.  There was less air in the container.

comprise/consist

Use comprise without 'of'.

e.g. The sample comprised 42 males & 47 females.

Use consist with 'of'.

e.g. Water consists of hydrogen and oxygen atoms.

its/it's

Use it's as a short form of 'it is'

Use its as a possessive

practice/practise

Practice is a noun.

e.g. I need more practice with this technique.

Practise is a verb.

e.g. I need to practise this technique.

Singular/plural confusion

Some commonly used words in the sciences have irregular plurals that can be confusing. The table below gives some examples.

Singular Plural
hypothesis hypotheses
criterion criteria
phenomenon phenomena
thesis theses
datum data
medium media
appendix appendices/appendixes (both correct)
bacterium bacteria
stimulus stimuli
index indices/indexes (but different meanings)
analysis analyses
axis axes
formula formulae/formulas (both correct)
basis bases
diagnosis diagnoses
parenthesis parentheses
genus genera