I am an English Literature teacher at university level, and a trained EFL teacher, so it's a bit embarrassing to have to ask this, but I can't find a satisfying answer anywhere else.

My students regularly use 'this' mid-sentence, usually after a comma. E.g., 'The room is small, this indicates that...'

I think it should read: 'The room is small. This indicates that...' or 'The room is small, which indicates that...'

I am fully aware of the rules (whether you adhere to them or otherwise) that govern the use of 'that' and 'which', but I've yet to find a convincing way to explain to my students that 'this' is incorrect mid-sentence.

At the moment I try to explain that 'this' should only follow a full stop or semi-colon as it refers to the subject of the preceding clause, but that's not actually an explanation of why 'this' is incorrect mid-sentence.

Of course, I may be completely wrong, and it's actually fine to use 'this' in this way.

Can anyone help with an explanation that I can offer my students?

  • 3
    The violation of punctuation conventions is easily addressed. A thornier problem is the fact that the referent for "this" is not always going to be clear. For that reason, it would be better to have the students avoid "this" and attempt to rephrase the idea, e.g. "The smallness of the room indicates..."
    – TimR
    Nov 20, 2015 at 13:58
  • 2
    As @Languagemaven points out, it's a "comma splice". But so is, for example, It's not a comet, it's a meteor. I rather like Barbara Wallraff's observation on that one: Punctuating this sentence with a semicolon would be like using a C-clamp to hold a sandwich together. My point being that you can't simply say It's a comma splice, that's why it's "ungrammatical". Nov 20, 2015 at 13:59
  • 3
    You could throw all kinds of grammatical rules at your students—which usually has no effect—or encourage them to learn to listen. "The room is small, this indicates …" is awkward to pronounce as a running sentence, with a large pause between the two parts—the kind of pause that's indicated by a period. Punctuation is better learned through listening, imho.
    – ralph.m
    Nov 20, 2015 at 14:14
  • 1
    @ralph.m: Listening AND talking. Nothing registers without feedback loop.
    – Ricky
    Nov 20, 2015 at 14:32
  • 1
    Or the sentence you wrote that violates your rules: "Of course, I may be completely wrong, and it's actually fine to use 'this' in this way." Nov 20, 2015 at 21:16

5 Answers 5


It's because you can't use a comma to separate two independent clauses without their being joined by a conjunction, etc. The type of sentence construction your students are writing is known as a "comma splice".

  • Probably worth mentiong that there are plentyof cases where 'this' can occur outside the restrictions the OP specifies, especially when there is a valid congunction. e.g. "The student failed, but this was because of health issues". Nov 20, 2015 at 18:03
  • Thanks for commenting, but I'm not sure what you mean. Nov 20, 2015 at 19:08
  • In paragraph 5 the OP gives his policy on the use of 'this' mid-sentence, which I believe is over-restrictive. Thought you might like to add that to your answer. It's not worth my making a separate answer for. Nov 20, 2015 at 19:28
  • 2
    But people can, and they do.
    – jobermark
    Nov 20, 2015 at 22:48
  • 1
    Right, just as people can, and do, make themselves intelligible...but no, not you Nov 20, 2015 at 22:56

There is nothing better than a dictionary when explaining to others in terms of grammatical usages.

If you look up "this", there is a specific usage which is similar to yours:

Referring to a specific thing just mentioned: 'They build the car in their Turin plant, and this brings the expected levels of quality.'

The dictionary uses "and" after a comma. This is an example that students should follow.

There is another example that doesn't use "and" after a comma as follows:

This is not a role model, this is a terrifying ideologue and a fundamentalist, if you will.

[Oxford Online Dictionary]

Here, "and" is not used because the subject of the second clause is the same as the first clause.

You have to explain to your students:

You can only omit "and" after a comma when the subject of the previous clause is the same as that of the second clause.

  • 3
    The second fragment needs a semicolon, IMO. Nov 20, 2015 at 15:14
  • 3
    Dictionaries are good for meaning. They don't normally get into details about grammar. You got lucky that there were relevant examples in that particular dictionary ... but even here it's sub-optimal, as it doesn't tell you why those examples are correct and the student's usage is not. (You can't expect the dictionary to list every correct sentence form, so not listing it doesn't tell you much.)
    – R.M.
    Nov 20, 2015 at 15:43
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    @Rathony There is something better than a dictionary when explaining grammatical usage: an actual grammar book. While dictionary examples may be grammatical (for the most part - many examples in the OED are archaic), they don't necessarily outline the full extent of what is and is not grammatical. Just because they omit an example with a particular construction or give an example with a different construction, that doesn't mean that the original construction is forbidden. -- The student's example is, indeed, bad grammar, but there's nothing on that dictionary page which says that.
    – R.M.
    Nov 20, 2015 at 16:10
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    @Rathony The examples you give aren't archaic, but some actual examples from the "this" page of the OED are: "Þis sigbecn þun setton." "This of Bavaria is a gallant and polite court." "This was years ago, Four hundred, full." (Note the OED and the Oxford Dictionary of English are distinct, but from the same publisher.) - Both dictionaries and grammar books take examples from the English language corpus (not from each other), but each focuses on different features and is optimized for different purposes.
    – R.M.
    Nov 20, 2015 at 18:44
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    @Rathony I suspect we may be talking cross purposes. I don't have an issue with your conclusions, mainly just your first sentence. "I looked up 'this' and was lucky enough to find example sentences which will help me explain things." would be fine, but to me it reads more "Pro tip: in the future, you can answer such questions yourself by just looking up the word in the dictionary; it will tell you if things are grammatical or not." The latter is not generalizable advice, for the above-stated reasons.
    – R.M.
    Nov 20, 2015 at 18:56

This is not quite an answer but rather a hypothesis that might prove helpful to you. If not, don't kill me.

As Lunguagemaven pointed out, technically, your students seem to be excessively fond of the comma splice. In reality, they're merely accustomed to talking (and thinking) in short block-like sentences that follow one another in quick succession. They are loath to pause after each sentence lest their listeners take advantage of it and start talking themselves. The resulting patterspeak is reflected in their writing.

One way to remedy this would be to teach them to write longer, more descriptive sentences (adjectives and adverbs galore). Instead of letting them write "This room is small," insist on details, metaphors, humor - anything. "This otherwise perfectly serviceable room with off-white walls and quaint-looking windows is ludicrously small." It would be pretty difficult not to pause and take a breath after a sentence of this length. And, just like "a good cigar is a smoke," a good dramatic pause is an invitation to put a period where it belongs.

  • The more likely reason they like 'this' in place of 'that' or 'which' is that the distinctions are different in English from those in most other languages. Also, It is officially correct in a wider variety of places. (As it is correct here.) But we prefer the other two, more specific forms for exactly that reason.
    – jobermark
    Nov 21, 2015 at 18:45

Your rule is overly broad. A case could be made for applying it to the example you give, but as a rule to state in such a broad way it is very flawed.

For example this sentence uses the word mid-sentence. What does this mean? I think that this means your rule doesn't work. Isn't this neat? I think that this rule needs to be thrown out. I don't know how this impacts your teaching, but this is still the case. I think I'm done with this answer.


Actually, it is not ungrammatical, it is just awkward.

The 'this' does not refer to the subject of the preceding clause, but to the whole clause itself.

The which/that distinction helps us in situations like this:

The parking space has a sign that [the sign] indicates it is for small cars.

The parking space has a sign, which [the clause] indicates it is special (even to those who cannot read.)

But not choosing means:

The parking space has a sign. This [which one?] indicates...

Many people only use this construction when they want to be pedantic. They are slowing you down by not giving expected grammatical clues.

Doing that and comma-splicing at the same time is not incorrect, it is just mean.


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