The 317.5km long Moscow Metro is the sixth longest subway system in the world. It is mostly underground, and serves the city of Moscow and the neighbouring towns Krasnogorsk and Reutov. State-owned enterprise Moskovsky Metropoliten owns and operates the metro system.
In prescriptive grammar, the topic sentence is the sentence in an expository paragraph which summarizes the main idea of that paragraph. It is usually the first sentence in a paragraph. Also known as a focus sentence, it encapsulates or organizes an entire paragraph. Although topic sentences may appear anywhere in a paragraph, in academic essays they often appear at the beginning. The topic sentence acts as a kind of summary, and offers the reader an insightful view of the writerâs main ideas for the following paragraph.
A topic sentence has several important functions: it substantiates or supports an essay's thesis statement; it unifies the content of a paragraph and directs the order of the sentences; and it advises the reader of the subject to be discussed and how the paragraph will discuss it.