This list of countries by rail transport network size based on International Union of Railways data ranks countries by length of rail lines worked at end of year updated with other reliable sources. These figures also include urban/suburban mass-transport systems; as well as lines which are not used for passenger services. 1 List.
Review with students what a topic sen-. tence is. (The topic sentence is the sentence. containing the main idea of a paragraph-. often, but not always, the first sentence in. the paragraph.) Put a couple of good models. from the daily newspaper on the overhead-.
A writer will state his/her main idea explicitly somewhere in the paragraph. That main idea may be stated at the beginning of the paragraph, in the middle, or at the end. The sentence in which the main idea is stated is the topic sentence of that paragraph. The topic sentence announces the general theme (or portion of the theme) to be dealt with in the paragraph. Although the topic sentence may appear anywhere in the paragraph, it is usually first â and for a very good reason.