find the main idea, main purpose, and topic

Overland transport in the United States was still extremely primitive in 1790. Roads were few and short, usually extending from inland communities to the nearest river town or seaport. Nearly all interstate commerce was carried out by sailing ships that served the bays and harbors of the seaboard. Yet, in 1790 the nation was on the threshold of a new era of road development. Unable to finance road construction, states turned for help to private companies, organized by merchants and land speculators who had a personal interest in improved communications with the interior. The pioneer in this move was the state of Pennsylvania, which chartered a company in 1792 to construct a turnpike, a road for the use of which a toll, or payment, is collected, from Philadelphia to Lancaster. The legislature gave the company the authority to erect tollgates at points along the road where payment would be collected, though it carefully regulated the rates. (The states had unquestioned authority to regulate private business in this period.)

This paragraph above mostly talks about ___ .

• Some important roads in Pennsylvania

• The history of transportation in Pennsylvania

• Pennsylvania's government authority to regulate private business

• Pennsylvania's history of transportation in modern era

The dominant salt in Death Valley is halite, or sodium chloride, but other salts, mostly carbonates and sulfates, also cause prying and wedging, as does ordinary ice. Weathering by a variety of salts, though often subtle, is a worldwide phenomenon. Not restricted to arid regions, intense salt weathering occurs mostly in salt-rich places like the seashore, near the large saline lakes in the Dry Valleys of Antarctica, and in desert sections of Australia, New Zealand, and central Asia.

*What is the main idea of the paragraph above?

• The subdominant salt in Death Valley

• Some restricted area in the seashore,

• The example of sodium chloride in East Asia

• The phenomenon of salts weathering

There, salty water rises from the groundwater table by capillary action through tiny spaces in sediment until it reaches the surface.

*The word "it" in line 9 refers to ___ .

• salty water

• groundwater table

• capillary action

• sediment

The interaction of improved processing and high demand led to the rapid spread of the cultivation of cotton and to a surge in production. It became the main American export, dwarfing all others. In 1802, cotton composed 14 percent of total American exports by value. Cotton had a 36 percent share by 1810 and over a 50 percent share in 1830. In 1860, 61 percent of the value of American exports was represented by cotton. In contrast, wheat and wheat flour composed only 6 percent of the value of American exports in that year. Clearly, cotton was king in the trade of the young republic. The growing market for cotton and other American agricultural products led to an unprecedented expansion of agricultural settlement, mostly in the eastern half of the United States---west of the Appalachian Mountains and east of the Mississippi River.

*This paragraph mostly talks about ___ .

• Low demand of the cultivation of cotton and to a surge in production.

• Wheat and wheat flour as the main commodity in American

• The production of cotton as the main American export

• The Appalachian Mountains residents history in Mississippi River

The growing market for cotton and other American agricultural products led to an unprecedented expansion of agricultural settlement, mostly in the eastern half of the United States---west of the Appalachian Mountains and east of the Mississippi River.

*The word "unprecedented" is closest in meaning to ____

• not seen before

• profitable

• slow

• never explained

In its early history, the violin had a dull and rather quiet tone resulting from the fact that the strings were thick and were attached to the body of the instrument very loosely.

During the eighteenth and nineteenth century, exciting technical changes were inspired by such composer-violinists as Vivaldi and Tartini. Their instrumental compositions demanded a fuller, clearer, and more brilliant tone that was produced by using thinner strings and a far higher string tension. Small changes had to be made to the violin's internal structure and to the fingerboard so that they could withstand the extra strain. Accordingly, a higher standard of performance was achieved, in terms of both facility and interpretation. Left-hand technique was considerably elaborated, and new fingering patterns on the fingerboard were developed for very high notes.

*What is the main idea presented in paragraph above?

• The violin has been modified to fit its evolving musical functions.

• The violin is probably the best known and most widely distributed musical instrument in the world.

• The violin had reached the height of its popularity by the middle of the eighteenth century.

• The technique of playing the violin has remained essentially the same since the 1600's.

Their instrumental compositions demanded a fuller, clearer, and more brilliant tone that was produced by using thinner strings and a far higher string tension. Small changes had to be made to the violin's internal structure and to the fingerboard so that they could withstand the extra strain. Accordingly, a higher standard of performance was achieved, in terms of both facility and interpretation. Left-hand technique was considerably elaborated, and new fingering patterns on the fingerboard were developed for very high notes.

*The word "they"above refers to ___ .

• Civaldi and Tartini

• thinner strings and a higher string tension

• small changes

• internal structure and fingerboard

Small changes had to be made to the violin's internal structure and to the fingerboard so that they could withstand the extra strain.

*The word "strain" above is closest in meaning to ___ .

• struggle

• strength

• strategy

• stress

Contemporary readers, forgetting the origins of western epic, lyric, and dramatic forms, are easily disposed to think of “literature” only as something written. But on reflection it becomes clear that the more critically useful as well as the more frequently employed sense of the term concerns the artfulness of the verbal creation, not its mode of presentation. Ultimately, literature is aesthetically valued, regardless of language, culture, or mode of presentation, because some significant verbal achievement results from the struggle in words between tradition and talent. Verbal art has the ability to shape out a compelling inner vision in some skillfully crafted public verbal form.

*What is the main point of the paragraph above ?

• Public performance is essential to verbal art.

• Oral narratives are a valid form of literature.

• Native Americans have a strong oral tradition in art.

• The production of literature provides employment for many artists.

Feeding postpones that moment until a young animal has grown to such a size that it is better able to cope. Young

that are fed by their parents become nutritionally independent at a much greater fraction

of their full adult size.

*The word "it" refers to ___ .

• feeding

• moment

• young animal

• size