The main line is the main outline of the story development of the novel, and the sub-line is the branch plot of the main line of the novel. Generally, the main line runs through the whole text, and the sub-line is just an interlude.
In the novel, the clues directly presented by the character activities or the development of events are called bright lines, while the clues indirectly presented by the character activities or events that are not directly depicted are called hidden lines.
There are no clues. If there are clues, they should be clues to events or characters.
The following are examples from other great masters:
Have you ever seen a bead curtain? Bar? The crystal beads are strung together with threads and used as space partitions. The thread of the article is like the thread on which these beads are strung, and the beads are the rest of the article.
Single thread: it is one main thread for beading;
Double thread: it is two main threads for beading;
Open thread: it is the red color that is very conspicuous for this main thread. The thread is obviously different from the crystal beads;
Dark thread: This is the main thread that uses a transparent plastic thread that looks very similar to the crystal beads. It seems difficult to distinguish.
Remember the metaphor above, and I believe you should know what the clue in the article means.