Section 13.1.2

Compound Sentences

A compound sentence contains two or more independentclauses. The independent clauses are joined in one of the following waysto indicate that they form one sentence.

• With a comma and a coordinating conjunction:

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Organic chemists have gained substantial command over the synthesis ofsmall complex molecules, but the goal of constructing largewell-defined molecules has been more elusive.

--"Dendrimer Molecules," Scientific American (modified)

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• With a comma and a correlative conjunction:

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In John Conway's famous game of "Life", there is a finite grid filled withcells. Either each cell is alive, or itis dead.

--Kai Wu, "Artificial Life," SciTech Magazine (modified)

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• With a semicolon:

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In 1931 Oppenheimer attempted to find an equation for the photon that wouldbe an analogue to Dirac's equation for the electron; he failedin this effort.

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• With a semicolon and a conjunctive adverb:

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By virtue of their prevalence alone, it is clear that mood disorders do notnecessarily breed genius; indeed, 1 percent of the generalpopulation suffer from manic-depression and 5 percent from a major depressionduring their lifetime.

--"Manic-Depressive Illness and Creativity," Scientific American(modified)

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Do not attempt to form a compound sentence by joining the independent clauseswith just a comma. Such a structure is called a commasplice.

The independent clauses that make up the compound sentence should be at leastapproximately equal in importance. If one clauseis clearly less important than the other(s), make the less important clause a dependent clause by introducing it with a subordinating conjunction. The resulting sentence willthen be complex rather than compound.

Weak

Jupiter has an enormous size and gravity [background]and the Galileo probe steadily gained velocity as it approached theplanet [focus].

Improved

Because Jupiter has an enormous size and gravity[background], the Galileo probe steadily gained velocity as itapproached the planet [focus].

--"Halo Nuclei," Scientific American (modified)

## Compound Sentences ##


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