Auxiliary parts of speech differ from significant (independent) in the fact that have no concrete lexical or grammatical meaning. Meanwhile about 25% of the speech make function words and parts of speech.
Auxiliary parts of speech are pretexts, the unions and particles. They do not change by the nature of or time, are not separate sentence parts. At each auxiliary part of speech the function. Pretexts help to express the relation of a noun, pronouns or a numeral to other words in the offer. They specify the meaning of a statement, connect words in the offer and create adverbial values. Pretexts always are before a word with which are used. In the offer "I come back Krasnoyarsk four days of a delay of flight" there are no pretexts. But in general it is possible to place them on sense. "From" - expresses the spatial relations. "In" - the temporary relations, "because of" - the reason or a circumstance. Competent use of pretexts does the speech competent. Such auxiliary parts of speech as the unions, connect among themselves homogeneous parts of the sentence or parts of a compound sentence. Conjunctions are subordinating and coordinating. "And", "@-@", "also", "too", "but", "but", "or", "however", "that", "or" - parts of a compound sentence connect. They are divided by functions on: connecting, adversative and dividing. The offer will be an example of use of the adversative union: "I arrived to it, but it already departed". "That", "that", "because", "as though" – all this examples of subordinating conjunctions. They connect parts of a complex sentence. On value they are divided on: izjyasnitelny, causal, temporary, target, conditional, investigative, concessive and comparative. For example, in the offer "They carelessly kicked a door as though here decent people do not go." Function at the union "as though" - to explain, explain, indicate what speak about. Also the function word can perform functions of an auxiliary part of speech. So, in complex sentences, it is relative pronouns and adverbs. "Which", "where", "who" "that", "where", "from where", etc. - their difference from the unions that they are sentence parts. Particles are also an auxiliary part of speech. They express different shades of value in the offer and serve for formation of forms of words. For example, "Let everything it will be cheerful!". Here the particle "let" forms an imperative mood of the verb "be". It is a form-building particle. Also particles are modal, they can express: denial, strengthening, question, exclamation, doubt, specification, restriction and instruction.