The knowledge of syntactical rules is important if we wish to form correct sentences that appropriately convey a given idea. An elliptical construction is one in which a word or phrase implied by context is omitted from a sentence, usually because it is a repetition of a preceding word or phrase. The three principal types of elliptical construction are as follows:

The given sentence is wordy because the phrase “exhibited an increase of” is repeated in each of the three clauses. To make the sentence more concise, “exhibited an increase of” was eliminated from the second and third clause. However, the meaning of the shortened sentence is still clear, based on the context.

In a sentence where repeated elements recur in more than one clause, a comma marks the elision of these words or phrases, and the clauses are separated by semicolons: “Igneous rock is formed from the cooling and solidification of magma of lava; sedimentary, from sedimentation of surface and underwater material; and metamorphic, from heat or pressure action on igneous, sedimentary, or another metamorphic type of rock.”

Elliptical constructions help us provide complicated information in a clear and concise manner. However, do remember to punctuate the sentence properly—as with most rules of grammar, these rules also establish convention and eliminate grey areas of expressing ideas, especially in academic writing.