The processes used in such combinations, as we have seen, are really but two in number,—coördination and subordination.
Coördination of clauses produces compound sentences or compound clauses; subordination of one clause to another produces complex sentences or complex clauses.
508. Every sentence, however long and complicated, belongs (in structure) to one of the three classes,—simple, compound, and complex.
SIMPLE SENTENCES
509. A simple sentence may have a compound subject or predicate (or both), and may also include a number of modifiers and complements.
Obviously, then, a simple sentence need not be short. It remains simple in structure so long as it contains but one simple or compound subject and one simple or compound predicate. Thus,—
1. You leave Glasgow in a steamboat, go down the Clyde fourteen miles, and then come to Dumbarton Castle, a huge rock five or six hundred feet high, not connected with any other high land, and with a fortress at the top.—Webster.
The length of this sentence is due partly to its compound predicate, partly to the modifier (and modifiers of the modifier) attached to the noun Dumbarton Castle.
2. He was little disposed to exchange his lordly repose for the insecure and agitated life of a conspirator, to be in the power of accomplices, to live in constant dread of warrants and king’s messengers, nay, perhaps, to end his days on a scaffold, or to live on alms in some back street of the Hague.—Macaulay.
This sentence is lengthened by means of a series of infinitives used as adverbial modifiers of the complement disposed (a participle used as an adjective). Each of these infinitives takes a complement or a modifier (or both).