From the school program it is known that the clauses which are grammatical not connected with sentence parts are parenthetic (i.e. not connected on a way of management, coordination, an adjunction). Parenthetic clauses express the relation speaking to the introduced idea, characterize a way of its registration. They have intonation of introductoriness which is expressed in faster pronouncing and depression of voice in comparison with the rest of the offer.
Parenthetic clauses can belong also to all offer, and to its certain part. Are expressed by them: - additional expressional and emotional shades ("I, to the horror, understood that I did"); - assessment of the reported fact telling degrees of reliability ("as a matter of fact", "needless to say", "without any doubt", "As sailors speak, wind grew stronger"); - assessment of the facts in terms of their ordinary ("as usual", "as usual"); - feelings of saying: joy, surprise, disappointment, a regret, etc. ("My hands, to my terrible disappointment, shivered"); - the sequence of statement, communication of thoughts ("So, you do not want to cross the road"); - ways and methods of registration of thoughts, the expressional nature of a statement ("To admit to tell in any time there was no such storm here"). A number of parenthetic clauses indicates a message source ("in terms of", "as is well-known"). The special group of parenthetic clauses is made by syntactic designs which are turned to the reader or the interlocutor. Their purpose is drawing attention to the stated facts, suggestion of a certain relation to reported ("Make favor, listen that I will tell you"). Being not syntactically connected with sentence parts, often parenthetic clauses carry out a constructive role and are necessary for its structure. Parenthetic clauses differ from parenthesises in the fact that they are more independent that is explained by their variety on the logical volume and structure. The main sphere of their use – oral speech to which they give intonational expressiveness often meet in artistic speech, but not in book where preference is given to shorter introduction units. Similar offers are most often laconic, seldom are widespread.