Complex Sentences
with finite & nonfinite clauses

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Complex Sentence Defined

A complex sentence combines a simple sentence (often called an independent clause) with a subordinate clause.  These sentences are the fundamental type used in academic writing--and thus a major feature in the reading and writing of ESL/EFL learners who are studying (or who wish to study) in the U.S. (or other English-speaking countries). 

Subordinate Clause Types

Complex sentences come in many varieties based on the types of subordinate clauses that are available in English.  In the Longman Student Grammar (and other studies of English grammar), subordinate clauses are divided into two major types: (1) finite clauses snf (2) non-finite clauses.  Let's go through these one by one. 

Finite Clauses

Finite clauses are the basic subordinate clauses that are the focus of most work with complex sentences and dependent clauses in ESL/EFL grammar/writing courses and materials.  The "finite" just means that there a full verb phrase--and that the clause has some type of "time" meaning.  Finite clauses include (1) adverbial clauses, (2) noun clauses, (3) wh-clauses, and (4) relative clauses.  In each of the following examples, the verb phrase is given in bold type to focus your attention on that feature of the clause.

Finite Clauses
Adverbial Clause 1. Because humans are not monkeys, we must be careful about extrapolating from animal studies to human behavior. 
Wh-Clause  2. We imagine how we appear to those around us. 
Noun Clause 3. For example, we may think that others see us as witty or dull.
Relative Clause 4. Cantonese (the language of Canton, which differs in sound from Mandarin roughly the way French does from Spanish) is the second most common Chinese dialect.

Non-Finite Clauses

Non-finite clauses are built around verbs that do not have tense or modality--verbs that are not sentence verb phrases.  These are clauses with (1) infinitives and (2) participles (both -ed and -ing). 

Non-Finite Clauses
Infinitive Clause 1. He wondered why he had forsaken physics to study human culture in the first place.
Present Participle Clause  2. Entering the world of the Yanomamo, the anthropologist experienced culture shock.
Past Participle Clause 3. Confused by the differences between his culture and theirs, he wanted to flee and return home.

Non-Finite Clauses & ESL/EFL Materials & Teachers

Some teachers prefer to call infinitives and participles phrases.  This terminology seems to be a reasonable response to a teaching reality: most learners have more trouble with the finite clauses than they do with non-finite clauses.  Moreover, sentences with infinitives don' t appear to be very "complex": I like to study grammar looks like a simple SVO with the infinitive as the direct object.  When teaching students how to write complex sentences, teachers are generally more concerned about the difficulties of getting the right verb tense (and all of it) in finite clauses; they don't want to complicate things by calling sentences with infinitives complex sentences.  Because one of the audiences for textbooks is the teachers who will use it, in a grammar textbook that I published titled Applied English Grammar, I decided to go with the tradition of calling infinitives and participles phrases.  I'm not sure I would make the same decision today, but I also do not think that it matters a great deal.  In one setting, I can talk about infinitive clauses and in another setting infinitive phrases.  I just advise that you be consistent in your usage--and that you follow whatever system is used in the textbook that you and the students are working with.

Participles as Adjectives vs. Participles as Adverbials

Consider these sets of made-up examples:

1a. The noise made by the car suggested an engine problem.
1b. Tired from the trip, we went to bed right after dinner.

2a.  The tall women standing in the corner are from Brazil.
2b.  Standing in the corner, the tall women watched the other people in the classroom closely.

1a and 2a show participle clauses that have adjectival function; they come after the noun and are attached to it and have become part of it.  They can be analyzed as reduced relative clauses:
1a. The noise that was made by the car suggested an engine problem.
2a. The tall women who are standing in the corner are from Brazil.
While the other clauses have the same types of words and the same organization, they have different functions--and are analyzed as coming from different sourses.  1b and 2b are actually adverbial in function and meaning.
1b. Because we were tired from the trip, we went to bed right after dinner.
2b. While they were standing in the corner, the tall women watched the other people in the classroom closely. 
Here's are authentic sentences from my sociology source.  They're from a chapter opener that tells the story of an anthropologist's encounters with another culture.
Anthropologist Napolean Chagnon was nearing the end of a three-day journey to the home territory of the Yanomamo, one of the most technologically primitive societies remaining on earth.

The anthropologist's clothes were soaked with perspiration, and his face and hands were swollenfrom the bites of innumerable gnats swarming around him.

He and his guide climbed from the boat and walked toward the village, stooping as they pushed their way through the dense undergrowth.

Entering the world of Yanomamo, Chagnon experienced a severe case of culture shock, personal disorientation that accompanies exposure 
to an unfamiliar way of life. 

Some twelve thousand Yanomamo live in villages scattered along the border of Venezuala and Brazil. 

Reassured that he would survive at least the afternoon, he 
was still horrified by his inablility to make any sense of the people 
surrounding him. 

Please email me your questions and comments. Thanks.