Topic sentences and signposts are like a writer’s paraphernalia, which he/she uses to make writings clearer to the readers. Topic sentences showcase the main plot of the paragraph and also help to establish a link between the current and the upcoming paragraph. With the help of topic sentences, the writer justifies the reasons for putting up the points in the essay, which further offer a clue to the reader in terms of what is in store for them in the upcoming paragraphs.
Topic sentences do not plainly state a fact about the main idea of the essay, but rather tend to argue making the main theme of the essay clear for the readers.
Although there is no rule to explicitly to describe how a topic sentence should be, however, topic sentences usually are two to three sentences long, depending on the construct of the sentence. For example, if it is two sentences long then the first sentence states a fact and the next one explains it further for the reader to ponder on. Topic sentences changes form as and when required, depending on the sentence construct. Few popularly used approaches in this context are complex sentences, bridge sentences, pivots and questions.
Signposts, on the other hand, changes the direction of the argument put forward by topic sentences, thus making an essay’s arguments visible to the readers and also justifying what the thesis claims.
Signposts act as tools to bring up the other part of the argument in front of the readers. They can act as speed breakers in an essay, in order to provide clarification about any historical background of an incidence, or some scholastic information about the plot of writing. It reminds the reader about the sole purpose of writing an essay, defining the purpose very closely for better understanding. They function as topic sentences in the whole section comprising of about one to two sentences at a stretch, which act as transition points in the section.
Topic sentences and signposts are both part of prescriptive grammar and act as an intermediate layer in the entire thesis creation process. Although the writer need not pay heed on these minor intricacies, however, these small things help the essay to be well defined and structured for the readers to understand better. It provides the essential prologue to a reader and lets the writer know, whether his writings are arguable or not. Thus, to understand these parts of grammar are equally important for a writer, as well the reader.