The main word is that from which the question is asked to dependent. For example, "reading a book": read what? – a book; "to walk in the yard": to walk where? – in the courtyard; "very nice": nice – how much? very. Way of subordinating relations in the expressions of the isolated coordination, governance and contiguity.
If the type of subordinating regard is the agreement, the form of the dependent word is consistent with the form of the main. The concept forms part of the gender, number and case: beautiful landscape, beautiful scenery, beautiful scenery. When changing, for example, the case of the main word, in exactly the same way changing the case of the dependent word. In such phrases the dependent word is usually an adjective and the main noun.
Control – method of communication in which the key word controls dependent with a specific case issue. Examples: "build a house" (accusative case), "seeing a Fox" (genitive), "sea noise" (genitive), "remembered the debt" (the instrumental case). The dependent word is a noun or a noun with a preposition.
Another way to link words in phrases – junction. There is only semantic (lexical) and prosodic communications, and grammatically this relationship is not expressed in any way. The dependent word is immutable, it can be an adverb or a gerund. For example: "long silent", "fun talk", "skipping", "was welcomed by smiling".
So, to determine the key word, set the phrase to the question. Do not confuse a phrase with a grammatical basis: in both the word shall be the primary, equal, and a question from one word to another ask will not work.
In the sentence "the sound of applause came from the circus" there are grammatical basis: "I left the circus". What kind of phrase is in this sentence? "Released under noise" (the main word is out, the question is – under what?); "the sound of applause" (the key word – the sound, the question – what?). In both phrases the type of communication word – of management.
Advice 2: How to determine the grammatical basis of the proposal
In order to understand the grammatical structure of the sentence, it is first necessary to find its footing. To do this, use the methods developed by linguists. When understanding the fundamentals offers you will be able to correctly place punctuation.
Learn what constitutes a grammatical basis. These are the main parts of the sentence - subject and predicate, which usually constitute the main meaning of the sentence. In some cases, sentences can contain only the subject or only the verb and a few words, performing the same functions of the main parts of the sentence.
Find subject. Most often it is expressed by a noun or pronoun. In this case, it necessarily stands in the nominative and answers the question "who?" or "what?". In the rare case the role of the object or subject of the action in the sentence plays a numeral, or even a whole phrase. If you see in the proposal a proper name in the nominative case, it is highly likely that it will be subject.
Define the predicate in the sentence. It refers to the action of the subject, which is the subject. In most sentences the predicate is the verb agreed with the subject in number and kind. Also, this part of the sentence can be expressed using verb phrases, verbal adjectives and even nouns. The verb should answer the question "who does?" or "what does?", grammatically agreed with the first part of the basis of the proposal.
Note in the found basis. Underline the subject with one continuous horizontal line, and the predicate two.
If subjects and predicates are several specify the grammatical structure of the sentence. If all of the subject and the predicate agree with each other grammatically and in meaning, this indicates a simple sentence. On the contrary, if they are independent and have an independent value, before you sentences with two or more bases, between which there is a coordinating or a subordinating relationship.