Clauses

The Grammar Rules for Clauses in English

1. A clause is a group of words that contains both a subject and a predicate but cannot always be considered as a full grammatical sentence. Clauses can be either independent clauses (also called main clauses) or dependent clauses (also called subordinate clauses).

2. An independent clause (or main clause) contains both a subject and predicate, can stand alone as a sentence (a simple sentence), or be a part of a multi-clause sentence. Coordinating conjunctions (and, but, for, nor, or, so, yet) are used to connect elements of equal weight such as two independent clauses, using a comma before the conjunction.
We visited Paris last September.
[independent clause functioning as a full sentence]

We visited Paris in September, and then we visited Berlin in October.
[two independent clauses connected by the coordinating conjunction and preceded with a comma]

3. A dependent clause (or subordinate clause) contains both a subject and a verb but cannot stand alone as a sentence. It must always be a part of a sentence, on which it depends for meaning. Reading a dependent clause on its own leaves the reader wondering where the rest of the information is. The following sections describe the different kinds of dependent clauses.

4. An adverb clause or adverbial clause (also called a subordinate clause) is a type of dependent clause which starts with a subordinating conjunction (e.g. because, although, when, if, until, as if etc.). It indicates a dependent relationship with information elsewhere in the independent clause that it modifies. Similarly to adverbs, adverb clauses usually answer questions such as: Why? How? When? Under what circumstances? When the adverb clause is written before the independent clause, separate the two with a comma.

In the following example pairs, see how the same information is given using a word, phrase or a clause.
We ate dinner at the hotel bistro.
[the adverbial phrase modifies the verb ate; it answers the question where?]

We ate dinner where all the locals usually go to.
[The adverb clause modifies the verb ate; it answers the question where?]

We wanted to go to the Louvre early.
[The adverb modifies the verb phrase wanted to go; it explains when?]

We wanted to go to the Louvre as early as we could.
[The adverb clause modifies the verb phrase wanted to go; it explains when?]

We visited Paris last September due to a business meeting.
[The adverbial phrase explains why?]

We visited Paris last September because we wanted to see the Mona Lisa at the Louvre museum.
[The adverb clause modifies the entire independent clause; it explains why?]

5. An adjective clause (also called a relative clause), just like an adjective, modifies the noun or pronoun preceding it (also called the antecedent). It starts with a relative pronoun (e.g. who, which, that, where, when, whose, whom, whoever etc.) which is also the subject of the clause.

In the following example pairs ,see how the same information is given using a word, phrase or a clause.
This is a great museum.
[the adjective amazing modifies the noun museum]

This is a museum that we visited last year.
[The adjective clause modifies the noun museum; that is a relative pronoun referring to the antecedent museum]

In Paris, we met good friends.
[the adjective good modifies the noun friends]

In Paris, we met friends whom we haven't seen for years.
[the adjective clause modifies the noun friends; whom is a relative pronoun referring to the antecedent friends]

6. Use who, whom, whoever and whomever when the adjective clause refers to a person or an animal with a name. Use which or that when the adjective clause refers to a non-person (thing) or an animal that is not a pet.
The French lady who was our tour guide turned out to be a distant relative of ours.
[the French lady is a person; who is used]

Our hotel, which was built in 1830, had an excellent bistro.
[our hotel is a thing; which is used]

7. When an adjective clause is non-restrictive (gives an extra piece of information not essential to the overall meaning of the sentence), separate it with commas from the rest of the sentence. Do not use that with non-restrictive adjective clauses.
The hotel that was built in 1830 has an excellent bistro
[The adjective clause is restrictive; only the hotel built in 1830 has an excellent bistro. The adjective clause is essential to the meaning of the sentence]
The hotel , which was built in 1830, had an excellent bistro.
[The adjective clause is non-restrictive; there may be more hotels with excellent bistros. The adjective clause merely adds extra information]

8. A noun clause functions as a noun, meaning that it can be a subject, object or complement in a sentence. It starts with the same words that begin adjective clauses: that, who, which, when, where, whether, why, how.
The Louvre museum was amazing!
[The Louvre museum = noun phrase as subject of sentence]

What we saw at the Louvre Museum was amazing.
[What we saw at the Louvre Museum = noun clause as subject of sentence]

We loved what we saw at the Louvre museum.
[what we saw at the Louvre museum = noun clause as object of the verb like]

The best thing we liked was what we saw at the Louvre museum.
[what we saw at the Louvre museum = noun phrase as complement of the verb was]

9. Do not confuse between adjective and noun clauses, as they begin with the same words. A word starting an adjective clause has an antecedent to which it refers, whereas a word starting a noun clause does not.
Our French friends know that we saw the new exhibition at the Louvre.
[that we saw the new exhibition at the Louvre = noun clause as object of the verb know]

The new exhibition that we saw at the Louvre was amazing.
[that we saw at the Louvre = adjective clause referring to the antecedent exhibition]

10. An elliptical clause may seem incorrect as it may be missing essential sentence elements, but it is actually accepted grammatically. As these clauses must appear together with complete clauses which contain the missing words, repetition is avoided by leaving the same words (or relative pronoun) out in the elliptical clause. This conciseness actually adds to the flow of the text and promotes writing that is more elegant.

In the following examples, the omitted words are given in parenthesis.
The Louvre museum was one of the sites (that) we did not want to miss.
[The relative pronoun that is omitted from the adjective clause]

After (we visited) the Louvre, we went out to dinner at a French bistro.
[subject and verb omitted from adverb clause]

The French make better croissants than the American (make or do).
[second half of comparison omitted]

Though (they) sometimes (appear) impatient and somewhat assertive, most French people are actually kind and warm-hearted.
[subject and verb omitted from adverb clause]
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This source is from http://www.whitesmoke.com/clauses-in-english

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Look at the sentences below.

• When I heard the disturbance, I dropped the files that I had been examining, then ran out into the corridor.
• I let the door slip from my fingers and it closed behind me.

In the first sentence it appears that there are as many as four separate segments which look like partial sentences connected to each other in different ways:

• When I heard the disturbance,
• I dropped the files
• that I had been examining,
• then ran out into the corridor.

In the second sentence there are two segments:

• I let the door slip from my fingers
• and it closed behind me.

We can call these segments clauses. Many sentences are short - they contain only one segment or clause. These single-clause units are called simple sentences. Examples of simple sentences might include:

• She has already read this book.
• The policeman asked me for some identification.
• The postman didn't arrive.
• No one knew the way.
• Why did he do it?
• Where did you last see your father?
• How much does this cost?
• Have you put the cat out?
• Will Bill be staying?
• Did they finish painting the house?

As you can see, it is not possible to divide any of these up into smaller segments that look like sentences. However, many sentences, both in the spoken and the written language, are often longer and more complicated than this simple type; such sentences are called multiple sentences. Sentence 2 (above) is an instance of a sentence which can be broken down into smaller segments or clauses.

Main clauses

Look at the three multiple sentences below:

• Harry put the phone down and he stood up.
• I gave him my address, but he didn't contact me.
• We could go to the cinema or we could stay at home.

The sentences can be divided into clauses as follows, and the main clauses are in bold.

• Harry put the phone down
• (and) he stood up.

• I gave him my address,
• (but) he didn't contact me.

• We could go to the cinema
• (or) we could stay at home.

In all three sentences each of the main clauses (those without the connecting words and, but and or) can stand on its own as an acceptable sentence - they all act as complete sense units in their own right. Clauses which can stand on their own in this way and have equal importance are referred to as main clauses; this will, of course, also include simple sentences, which contain only one clause. Sentences which are constructed using the linking words and, but, or and the few words which can be used in the same way, like also, too, yet, are called compound sentences. These linking words for compound sentences are known as coordinators since they serve to connect main clauses on an equal footing.

Subordinate clauses

The construction of compound sentences is essentially quite straightforward since we only have to take two or more simple sentences and insert a basic coordinatingword like and, but and or. There are, however many more ways in which clauses can be connected to each other to form longer sentences. The following are just a few examples of how clauses can be conjoined. The main clauses are in bold.

• After he left work, he headed straight for the hotel.
• We're going to have to take the train because the car's broken down.
• If you heat water, it boils.
• Although she's the best in the class, she did badly in the exams.
• While I'm out, could you tidy up a bit?

If you examine the sentences carefully, you will notice that only one of the clauses in each sentence can stand alone as a complete idea; these are shown in bold. The remaining clause in each sentence feels unfinished when used on its own. For example a native speaker would find the sense of 'although she's the best in the class' to be incomplete without a second clause expressing an unexpected contrast, in this case 'she did badly in the exams'. The clause which can stand alone is called a main clause, while the clause which depends on the main clause is said to be subordinate.
The range of linking words used with subordinate clauses is much wider than with the linkers in compound sentences. A short list would include:

• Time : after, before, as soon as, while, when, as
• Cause : because, since, as,
• Condition : if, provided that, as long as, unless
• Concession : although, though, even though
• Relative : which, who, that, where, whose

These different types of sentence structure will be examined in more detail in other sections of this guide. Sentences which are made up of clauses joined in this way are known as complex sentences. Here is an example:

• When I heard the disturbance,
• I dropped the files
• that I had been examining,
• then ran out into the corridor.

The main clause here is b since this can be used on its own as a complete sense unit.
Note that every sentence needs a subject telling us who or what is doing the action. In these sentences the subject is in bold:

• The man was clearly in pain.
• The child was sitting beside the door of my old car.
• The old olive tree was still producing wonderful olives.
• The man wearing the old red hat was walking slowly down the road.

One feature of the levels of sentence and clause is that they both need to include a person(s) or thing(s) carrying out some sort of action. The word denoting the action in a sentence or clause is called a verb, while the person or thing performing the action is typically a noun acting as the subject. The presence of this structure subject + verb, indicates that the collection of words is either a sentence or a clause; without this structure, a string of words is referred to as a phrase.
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This source is from http://www.waylink-english.co.uk/?page=31020

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Types of Clause

A clause is essentially a phrase, but with both a subject and predicate (more on those in the next post). Clauses are either dependent or independent. An independent clause can exist by itself as a complete sentence (as in “I love grammar.“), while a dependent clause cannot.

Dependent or Subordinate Clauses

A dependent or subordinate clause depends on an independent clause to express its full meaning (as in “Because I love grammar.”). These clauses begin with a dependent word, like a subordinating conjunction or a relative pronoun.
Dependent clauses can function as nouns, adjectives, and adverbs:

• Noun Clause – “The boy wondered if his parents bought him what he wanted for Christmas.” A noun clause can replace any noun in a sentence, functioning as a subject, object, or complement (see English Grammar: Basic Sentence Elements).

• Adjective Clause (or relative clause) – “I listened to the song that you told me about.” An adjective clause describes a noun just like an adjective. Which song? The new song, the good song, the song that you told me about. Often called relative clauses, they’re either restrictive or nonrestrictive (also called defining and non-defining, essential and nonessential, or integrated and supplementary):
  • Restrictive Clause – “The building that they built in San Francisco sold for a lot of money.” A restrictive clause begins with a relative pronoun like that or who (or sometimes which – see Which Versus That). It specifies or restricts the noun; in this case, it specifies which building the speaker is referring to. Note: the relative pronoun is often omitted (“The building (that) they built”), leaving what is called an elliptical clause or contact clause.
  • Nonrestrictive Clause – “The building, which they built in San Francisco, sold for a lot of money.” A nonrestrictive clause begins with a relative pronoun like which or who. It adds extra information about an already-specific noun; in this case, there’s only one building to talk about, whereas the example for the restrictive clause implies that there could be several buildings.

• Adverb Clause – “I’ll do the laundry when I’m out of clothes.” Like all adverbials, adverb clauses express when, where, why, and how something occurs. A dependent clause is an adverb clause if you can replace it with an adverb, as in “I’ll do the laundry later.”

Note: appositives can include clauses, but I’ve yet to find a source mentioning an “appositive clause.” They’re generally regarded as a type of noun phrase, even though they can be restrictive or nonrestrictive like relative clauses.
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This source is from http://learningnerd.wordpress.com/2006/09/08/english-grammar-types-of-clauses/