3. Sentences

Sentences can be categorized based on how many β€œthoughts” (clauses) are joined together.

Here is the breakdown of Simple, Compound, Complex, and Compound-Complex sentences.

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3.1. 1. Simple Sentence

A simple sentence consists of one independent clause. It has one process (verb) and describes one event or fact.

  • Biology: The cell membrane is semi-permeable.

  • Chemistry: The acid reacts with the metal.

  • Physics: Gravity pulls objects toward the center of the Earth.

  • Earth Science: Tectonic plates move very slowly.

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3.2. 2. Compound Sentence

A compound sentence joins two independent clauses together, usually with a coordinating conjunction like and, but, or, or so. Both clauses are equally important.

  • Biology: The heart pumps blood and the lungs provide oxygen.

  • Chemistry: The mixture turned blue but the temperature remained constant.

  • Physics: The mass increased so the acceleration decreased.

  • Earth Science: Some plates collide or they slide past each other.

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3.3. 3. Complex Sentence

A complex sentence joins one independent clause with one or more dependent clauses.
It uses subordinating conjunctions like because, although, if, since, or while.

  • Biology: The plant wilted because it lacked sufficient water in its vacuoles.

  • Chemistry: Although the catalyst was added, the reaction remained slow.

  • Physics: The circuit is complete if the switch is in the β€œon” position.

  • Earth Science: While the oceanic plate subducts, it creates deep-sea trenches.

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3.4. 4. Compound-Complex Sentence

A Compound-Complex Sentence contains at least two independent clauses and at least one dependent clause.
It allows you to explain complex relationships in a single sentence.

  • Biology: The mitochondria produce energy and the ribosomes create proteins because the cell needs these resources to survive.

  • Chemistry: The solution bubbled and it turned green after the reactive metal was dropped into the beaker.

  • Physics: The car accelerated down the ramp and its velocity increased as the potential energy converted into kinetic energy.

  • Earth Science: The continental plates crumpled to form mountains but no subduction occurred since both plates had the same low density.

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3.5. Summary Table