What one sentence does for the whole paragraph

Grade 8 Reading Worksheet

Circle the best answer.

1. Read this first

   When the Plains Blew Away (article)

   [1] In the 1930s, a long drought settled over the southern Great Plains, and farmers watched their crops wither in fields that had once produced record harvests. [2] The disaster that followed, however, was not caused by dry weather alone. [3] Human decisions made in the previous decades had left the land badly exposed.

   [4] During and after the First World War, high wheat prices encouraged farmers to plow up millions of acres of native prairie grass. [5] The deep, tangled roots of that grass had held the soil in place for thousands of years, even through earlier droughts. [6] Once the roots were torn out, the bare soil lay open to the wind, and farmers often left fields unplanted between harvests, which exposed it still further. [7] When the rains failed, the loose topsoil dried to powder, and winds lifted it into towering dark clouds that people called black blizzards. [8] One of the worst of these storms, on April 14, 1935, came to be known as Black Sunday. [9] Weather, then, supplied the trigger, but plowing had supplied the fuel.

   [10] The federal government responded with programs that taught farmers to plow along the contours of a slope and to plant rows of trees as windbreaks. [11] Those practices helped keep topsoil in place after the drought finally ended. [12] Historians now treat the Dust Bowl as a warning about plowing land that had stayed in place for thousands of years only because of the grass above it. [13] In their view, the storms were a natural hazard made far worse by human choices.

2. 1.

   Ari reads the Dust Bowl article. How does sentence [5] change what the reader understands about the plowing in sentence [4]?

   • It shows that earlier droughts on the Plains had not done any damage to the land.
   • It reports the wind damage that followed the plowing, so that [6] can then explain the roots.
   • It adds that the prairie grass was very old, which gave farmers good reason to respect it.
   • It shows why the plowing mattered: the roots it destroyed had been holding the soil in place.
3. 2.

   Bo thinks about cutting sentence [9], "Weather, then, supplied the trigger, but plowing had supplied the fuel." What would paragraph 2 lose?

   • The description of the programs that taught farmers to plow along the contours of a slope.
   • The statement that joins the weather and the plowing into one explanation of the disaster.
   • The fact that the rains failed and the loose topsoil dried to powder before the storms came.
   • The name and the date of one of the largest storms, which [8] gives as Black Sunday.
4. 3.

   Esme wants to state the idea that paragraph 2 builds. Which statement does that best?

   • High wheat prices pushed farmers to plow up millions of acres of native prairie grass across the southern Plains.
   • The federal government taught farmers new practices that helped keep the topsoil from blowing away.
   • Farmers alone caused the disaster, and the weather had little to do with how it unfolded.
   • The drought only triggered the disaster; earlier plowing had removed the roots that kept the soil in place.

5. Climbing Between Oceans (article)

   [1] When the Panama Canal opened in 1914, it shortened the voyage between the Atlantic and Pacific oceans by thousands of miles. [2] Ships no longer had to sail around the southern tip of South America. [3] Yet the most striking feature of the canal is not its length but the fact that its middle section lies well above sea level.

   [4] Engineers faced a difficult problem, because the land between the two oceans rises into hills, and a ship cannot simply sail through a flat trench at sea level. [5] Their solution was a system of locks, which are chambers with gates at each end that raise or lower ships in steps. [6] On the Atlantic side, a ship enters the first lock, the gates close behind it, and water flows in from the lake above to lift the vessel. [7] No pumps are needed, since gravity alone moves the water downhill from one chamber to the next. [8] After three such steps, the ship has been raised about eighty-five feet to the level of Gatun Lake, a huge reservoir created by damming a river. [9] The ship then crosses the lake under its own power and is lowered by another set of locks on the far side. [10] Each crossing therefore uses a great deal of fresh water, which is why the canal depends on the heavy rains of the region.

   [11] Engineers later added a wider set of locks, which opened in 2016, to accommodate bigger ships. [12] The basic principle, however, is the same one that the original builders used.

6. 4.

   Jun reads the Panama Canal article. How does sentence [7] refine the description of the first lock in sentence [6]?

   • It repeats that water flows in from the lake above, using different words from [6].
   • It explains why the ship must cross Gatun Lake under its own power, as sentence [9] does.
   • It shows that the canal uses less energy than any other way of moving ships between oceans.
   • It answers a question [6] raises by showing that gravity, not machinery, moves the water.
7. 5.

   Kira thinks about cutting sentence [4] from paragraph 2. What would the paragraph lose?

   • The reason the canal depends on the heavy rains of the region, which only [4] explains.
   • The fact that ships save thousands of miles by using the canal instead of sailing around South America.
   • The problem that makes locks necessary, so that [5] would answer a question the reader was never given.
   • The definition of a lock as a chamber with gates at each end that raises or lowers ships.
8. 6.

   Luz wants to state the idea that paragraph 2 builds. Which statement does that best?

   • Locks use water that flows downhill to lift ships over high ground, at a cost in fresh water.
   • Ships are raised about eighty-five feet to Gatun Lake in three steps on the Atlantic side.
   • The canal runs without fresh water because gravity alone does the work in each of the locks.
   • A wider set of locks, opened in 2016, lets the canal handle larger ships than before.

9. A Garden Built by Animals (article)

   [1] Coral reefs cover less than one percent of the ocean floor, yet they shelter about a quarter of all marine species. [2] A reef looks like a garden of stone, but it is actually built by tiny animals called coral polyps. [3] Understanding how these animals live helps explain why reefs have become so vulnerable to warming seas.

   [4] Each polyp shares its body with microscopic algae that live inside its tissue. [5] The algae use sunlight to make sugars, and the coral absorbs much of that food, which is why reefs thrive in clear, sunlit water. [6] In return, the polyp gives the algae shelter and the chemicals they need. [7] The algae also supply the brilliant colors for which reefs are known. [8] When the water stays several degrees warmer than usual for weeks, the algae begin to produce harmful compounds, and the coral expels them. [9] With the algae gone, the coral's transparent tissue reveals the hard white base beneath, an event called bleaching. [10] A bleached coral is still alive, but it has lost its main food supply and may starve if conditions do not improve. [11] If the water cools in time, new algae may settle in, and the reef can recover.

   [12] Scientists therefore monitor ocean temperatures closely, because a few weeks of unusual heat can change the fate of a reef for decades. [13] Early warnings allow nearby communities to reduce other pressures, such as pollution, while the reef is weakened.

10. 7.

    Milo reads the coral article. How does sentence [6] change the picture of the partnership given in sentence [5]?

    • It shows that the algae could not survive anywhere except inside a living coral polyp.
    • It repeats that reefs thrive in clear, sunlit water, using different words from sentence [5].
    • It shows the exchange runs both ways: the coral also gives the algae something, so neither is only a host.
    • It shows that the algae feed the coral while the coral gives the algae nothing in return, not even shelter.
11. 8.

    Pia wants to state the idea that paragraph 2 builds. Which statement does that best?

    • A coral depends on algae, unusual heat can break that partnership, and the coral may recover.
    • Scientists watch ocean temperatures because a few weeks of heat can change a reef for decades.
    • Corals have algae in their tissue that give them food and bright colors.
    • Warm water ends the life of a coral at once, so a bleached reef cannot recover once it has turned white.

12. The Teenage Body Clock (article)

    [1] Many teenagers are told to go to bed earlier, yet doing so often fails to work. [2] Sleep researchers explain that the problem is rooted in biology, not laziness. [3] During puberty, the internal clock that governs sleep shifts later in the evening.

    [4] The brain releases a hormone called melatonin to signal that it is time to sleep. [5] In children, the release begins in the early evening, but in teenagers it starts about an hour or two later. [6] A fifteen-year-old who lies down at nine may therefore be wide awake, simply because the brain has not yet received its signal. [7] The same shift pushes the natural waking time later in the morning. [8] Teenagers need roughly eight to ten hours of sleep, so a student who must rise at six often falls short of what the body requires. [9] Over weeks, that shortfall is linked to trouble concentrating, lower grades and a greater risk of accidents. [10] For these reasons the American Academy of Pediatrics has recommended that middle and high schools start no earlier than 8:30 a.m.

    [11] Some districts that moved their start times reported that students slept longer and were less likely to doze in class. [12] Others found that the change was hard to fit around buses, sports and family schedules. [13] Researchers therefore advise districts to weigh the sleep benefits against these practical costs before choosing a new schedule. [14] Their studies suggest that the health benefit is real, but that a successful change needs careful planning.

13. 9.

    Ren reads the article on teenagers and sleep. How does sentence [6] develop the point made in sentence [5]?

    • It applies the later release in [5] to one evening, showing what the shift means for a teenager.
    • It shows that teenagers who go to bed at nine will lie awake for hours before they sleep.
    • It explains why teenagers need eight to ten hours of sleep, as sentence [8] does.
    • It repeats that melatonin is released later in teenagers than in children, using an example.
14. 10.

    Zee wants to state the idea that paragraph 2 builds. Which statement does that best?

    • Melatonin is released an hour or two later in teenagers than it is in younger children, as sentence [5] explains.
    • Teenagers' body clocks run later, so early school starts cut into needed sleep, and later starts are advised.
    • Teenagers sleep too little because homework and sports keep them up, so later starts would not help.
    • Some districts that moved their start times saw longer sleep, though others faced scheduling problems.