Associative sentences with a colon consist of two or more parts, each of which has a specific meaning. The choice of this or that punctuation mark depends on him.
Colon in non-union compound sentence
1. This punctuation mark is placed if the next sentence (or a group of them) indicates the reason due to which what was said in the first happened. For example: "Andrey failed to arrange his brother as a master's apprentice: such young people were not taken there", "The sailors remained to sleep on the deck: it became unbearably stuffy below"
2. The colon in an allied compound sentence is also used when the next sentence (or a group of them) reveals the essence of the entire first sentence or one of its members. Then between its constituent parts, instead of a punctuation mark, it is easy to insert namely (an explanatory union). For example: “The house slowly began to make noise: at one end the door creaked; steps were heard in the yard; someone sneezed in the room”, “Soon I found happiness: to medaughter returned . A colon is put between several parts of such a sentence and when the first contains pronominal words.
The specific meaning of the words so, one, such, such, etc. is interpreted by the second part. For example: "All the people there are like this: a gossip sits on a gossip and drives a gossip", "One thing was clear: he would never come back." It should also be clarified that in a complex non-union sentence, one pronominal word is fully explained by the second part. This is the case when a colon is used after it. For example: "I ask you only one thing: decide quickly." And in a simple non-union sentence, it is supplemented only with an explanatory word, after which a dash is placed. For example: "In relations with strangers, the father demanded only one thing - to maintain decorum."
3. A colon in a non-union sentence is also used when the first sentence contains verbs look around, look out, listen, as well as those that denote an action that warns of what will be discussed later. Instead of a punctuation mark between its parts, it is easy to insert a union that or even a combination of words: and noticed that; and saw that. Sometimes in these cases they put a dash, although it is still preferable to put a colon. For example: "I looked out the window: stars appeared in the clear sky", "I looked around: the night triumphed and reigned all around." In these examples, the second sentence reveals the meaning of the first, complements it.
4. The colon in a non-union complex sentence is also used if the next part of it is presented as a direct question. For example: "I was walking now, talking to you and thinking all the time: why don't they change?", "You better tell me this: is it true that you are still in love with her?"
Colon in non-union compound sentence in newspaper headlines
When the title of an article splits into two parts - this is a separate case of setting this punctuation mark. The nominative theme - the first part of the title - indicates the problem as a whole, the person, the place of action, etc. And the continuation of the title already specifies what was mentioned at the beginning. For example: "Children: desirable and not so desirable".
