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b2B2 Upper-Intermediate EnglishComplex sentencesWritingabout 20 min

Building complex sentences

Combine ideas into varied, complex sentences — subordination, embedding and sentence variety — for better writing.

In this lesson you will

  • Combine simple sentences with subordination
  • Embed information with relative and participle clauses
  • Vary sentence length and structure

Learn

Subordinating words make one idea depend on another: although, because, since, while, whereas, unless, once, until, so that, even though. *Although the plan was ambitious, it succeeded because everyone worked together.*

Embedding: add details with relative clauses, participle clauses and appositives (a noun phrase that renames): Lagos, Nigeria’s largest city, is growing rapidly.

Variety: mix short sentences for impact with longer ones for explanation; vary sentence openings (a linker, a participle, a prepositional phrase).

Avoid: run-ons (joined with just commas), fragments (no main verb) and sentences so long that the reader gets lost.

Examples

  • Having grown up by the sea, she found the city suffocating, although she loved its energy.
  • The museum, which opened last year, attracts thousands of visitors who come to see its famous collection.
  • Prices rose. Sales fell. Nobody was surprised.
  • Unless the council acts now, the problem, already serious, will get worse.

Vocabulary

subordinate clause

a clause that depends on the main clause

appositive

a noun phrase that renames the noun before it

run-on sentence

two sentences joined incorrectly

fragment

an incomplete sentence

ambitious

needing a lot of effort to succeed

Practice

1 / 7

Which is a run-on sentence?

Speaking

Describe your hometown in five complex sentences, each using a different technique (subordination, relative clause, participle clause, appositive, contrast).

Recording isn’t available in this browser. You can still practise: say your answer aloud, then type what you said.

Writing

Rewrite this paragraph as 3–4 varied, complex sentences (100–130 words): “The town is small. It is near the mountains. Many tourists visit. They come in winter. They ski. The town needs more hotels. The council has a plan. Some residents disagree.”

  • ☐ At least two subordinating conjunctions
  • ☐ A relative or participle clause
  • ☐ An appositive
  • ☐ No run-ons or fragments
0 / 100+ words

Lesson quiz

1 / 5

“Paris, the city of light, …” — the underlined phrase is an…

Review

Key points

  • Subordination with although, because, unless, once…
  • Embedding: relative clauses, participles, appositives.
  • Vary length and openings; avoid run-ons and fragments.

What you learned

  • ✓ I can write complex sentences.
  • ✓ I can embed information.
  • ✓ I vary sentence structure.

Grammar reference: Sentence structure and word order, Conjunctions and linking words, Relative clauses: who, which, that, where, whose