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Academy11+

11+ English · Topic explained

Simple, compound and complex sentences

Why do some sentences have one idea, and others have two or three?

The big idea

Simple has one main clause, compound joins two main clauses, and complex adds a subordinate clause.

Picture it

Think of train carriages: one carriage (simple), two equal carriages coupled together (compound), or a carriage towing a trailer that can't move on its own (complex).

Key words

clause
A group of words with a subject and a verb.
main clause
A clause that makes sense on its own.
compound sentence
Two main clauses joined by and, but, or, so (or a semi-colon).
complex sentence
A main clause plus at least one subordinate clause.

Worked examples

  1. 1Warm-up

    The dog barked.

    • One subject (the dog), one verb (barked).
    • One main clause: a simple sentence.
  2. 211+ standard

    The dog barked, and the cat ran away.

    • Two main clauses joined by and.
    • Each could stand alone: a compound sentence.
  3. 311+ standard

    The cat ran away when the dog barked.

    • "when the dog barked" can't stand alone: it's a subordinate clause.
    • Main + subordinate = a complex sentence.
  4. 411+ standard

    The tired, muddy dog with the red collar barked loudly at the postman.

    • Long, but only one verb: barked.
    • Still one main clause, so still a simple sentence.

The common mistake

The mistake

A long sentence must be complex.

Instead

Length doesn't matter: count the clauses.

Why: A long sentence with one main clause and no subordinate clause is still simple.

Where it comes up in the 11+

Questions ask you to name the sentence type, or to join two sentences correctly, especially in GL SPaG sections.

The video

Video coming soon

We're making a short video that explains simple, compound and complex sentences step by step. Until then, everything it covers is on this page.

Free printable

Simple, compound and complex sentences worksheet

Practice questions on this topic to print and try on paper, at home or on the way to school.

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Quick quiz

Have a go first, then tap to see the answer.

  1. 1. What type is: "I finished my homework, so I watched TV."

    • simple
    • compound
    • complex
    Show the answer

    compound

    So joins two main clauses that could each stand alone.

  2. 2. What type is: "Although it was late, we kept reading."

    • simple
    • compound
    • complex
    Show the answer

    complex

    "Although it was late" is a subordinate clause; "we kept reading" is the main clause.

  3. 3. What type is: "After lunch, the class walked to the museum."

    • simple
    • compound
    • complex
    Show the answer

    simple

    "After lunch" has no verb, so it's a phrase. There's only one clause.