This question asks about (teaching) the distinction between complex and compound sentences.

I have managed to read really quite widely in linguistics for more than fifty years without ever as far as I can recall encountering this distinction. To me it appears completely pointless and nitpicking.

Would somebody please enlighten me why it might be of any interest or value to make the distinction, never mind teach it?

  • Typo: recall. Which form are you more familiar with; complex or compound? I'm guessing the latter, in which case could you define what is a compound sentence?
    – Mari-Lou A
    Jan 13, 2014 at 20:44
  • I don't know. I've probably met both and taken them as alternative terms.
    – Colin Fine
    Jan 13, 2014 at 21:42
  • I'm also not particularly familiar with dependent vs independent clause: I suppose the latter is much the same as what I learnt as a subordinate clause.
    – Colin Fine
    Jan 13, 2014 at 21:44
  • judge/verb/noun/of - I know but it's a test (the comment that is).
    – Frank
    Jul 20, 2014 at 15:01
  • @ColinFine, as far as I know dependent clause and subordinate clause are synonyms. The other type of clauses (i.e. non-subordinate clauses) are called independent clauses; what term for non-subordinate clauses have you been familiar with? Feb 26, 2020 at 10:22

3 Answers 3


I know a grammarian who maintains that it is senseless to analyse English as it is commonly spoken purely from a syntactic standpoint (while totally supporting syntactical analysis as an indispensable tool). Note however the confusion that can result from a semanto-syntactic approach:

.3. I come bearing soup, for Kate is sick.

.4. I come bearing soup, because Kate is sick.

In my book, sentence . . . 3 [is] compound, . . . conjunctive adverbs, and here FANBOYS, are both ways of linking independent clauses, and, therefore, we call them compound sentences.

Your last sentence uses the subordinating conjunction "because." With the use of "because," the second clause becomes a dependent one. It can't stand alone: "Because Kate is sick" is an incomplete thought. That's why this is a complex sentence.

Sentences (3) and (4) look suspiciously similar to me both syntactically and semantically.


The syntax/semantics overlap/divide can be illustrated in a few sentences.

John is tall and the car needs diesel.

(grammatical; compound; unacceptable in all but the most contrived contexts as joining two totally unrelated ideas)

John is tall and Sally is even taller.

(grammatical; compound; acceptable in that the coordinator connects two related ideas) (note however that 'Sally is even taller,' though an acceptable sentence, cannot be said to be 'semantically independent' as it needs prior context to make sense).

I come bearing soup, for Kate is sick.

I come bearing soup, because Kate is sick.

(grammatical if archaic; traditionally classified differently. 'Kate is sick' is certainly a main clause, in each case; the connecting word ('for' or 'because') while normally deducible and omissible [I come bearing soup – Kate is sick.] is, strictly, required to show the relationship (reason) between the first and second clauses. This embodies the idea of 'dependence' for 'for/because Kate is sick' if not being the usual usage.

  • I agree. In that case, at least, the distinction seems wholly spurious to me. But I don't grasp what your grammarian means.
    – Colin Fine
    Jan 13, 2014 at 21:47
  • There's a temptation to look at the similarities of surface structures of various constructions, at the expense of acknowledging deeper differences, and to slap on accepted and useful syntactic analyses in similar-looking cases where to do so is unjustified. I've come across the claim that both 'a bone' and 'a walk' are DOs in: 'He took the dog a bone' and 'He took the dog a walk'. I've even seen 'She led them a merry dance' classified as a ditransitive construction in one reference work. NP1-V-NP2-NP3 should not simply be labelled a 'ditransitive construction' without reference to meaning. Jan 14, 2014 at 7:35

Readers will often perceive texts that consist of mostly simple or compound sentences as uninteresting or written by immature writers. This is even more the case when the compound sentences consist of several independent clauses strung together with and's, so's and but's (so-called rambling sentences).

As OWL at Purdue states:

Adding sentence variety to prose can give it life and rhythm. Too many sentences with the same structure and length can grow monotonous for readers. Varying sentence style and structure can also reduce repetition and add emphasis.

Young writers need to be taught to recognize compound sentences and practise ways of converting them to complex or compound-complex sentences when appropriate. Understanding the composition of the four correct sentence types is helpful in identifying and avoiding problematic sentences such as run-ons, comma splices, and fragments.

  • Right. So its importance is primarily stylistic?
    – Colin Fine
    Jan 13, 2014 at 21:45

I always understood it to be intended to help us focus on the difference between a dependent and independent clause. This distinction helps us recognize and form a complete, stand alone expression and to differentiate it from a phrase or fragment that cannot (at least in the context of the sentence in question).

Understanding what is needed to make a complete, independent clause would then allow us to form clear sentences. Once we understand that, we can build more complex ones. And after that, we may learn how to slice through the rules with abandon for literary effect, but using a saber that we have honed through knowledge, not forged by accident.

  • Again, there's the semantics / syntax grey area. In the attempted analysis in the article OP links to, we read 'It can't stand alone: "[b]ecause Kate is sick" is an incomplete thought. That's why this is a complex sentence.' But the fact that "for Kate is sick" is nigh-on identical seems to have escaped the analyst, and he misanalyses in order to keep in with the FANBOYS police. In one sense, in say "Kate is sick – I brought her some ipecacuanha," the second clause, though obviously a main clause, is not in this sentence a <complete, stand alone expression, expressing a complete thought> : ... Jan 14, 2014 at 7:51
  • . . . for that, we NEED a semantically-loaded connector to express the speaker's whole thought here (so? though? because!?). I'm saying that both meaning and structure have to be taken into consideration when studying linguistics. Often, one or the other is stressed at the expense of the other (which is fine provided that the balance is restored later in the argument), or the approaches are confusingly entangled. Jan 14, 2014 at 7:54

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