Marisol Vane repairs tower clocks. She opens every talk the same way: "A clock is any machine that keeps time by counting something steady." How does the author first introduce the idea of a clock?

Some birds store food for winter. The gray jays of Ashbrook Forest tuck thousands of seeds into bark each fall and find them again in January. What does the second sentence do for the first?

The town of Kelder closed its main street to cars. Shop owners expected to lose business. Three years later, sales downtown had risen and foot traffic had doubled. What does the last sentence add?

Engineer Dev Rao studies how bridges sway. One windy morning in Halden he felt a footbridge shudder under his own feet, and he spent the next year measuring it. How does the author develop Rao?

Night skies over Verrick County are growing brighter. A survey found that 34 of the county's 40 towns now keep their streetlights on all night. How does the author develop the claim in the first sentence?

A marsh acts as a sponge. Dry ground sheds a heavy rain in minutes, while a marsh holds that same rain for days and lets it out slowly. Which developing move does the second sentence make?

Rain fell for nine days. The Tallow River rose over its banks, the earth levee soaked through, then slumped, and by dawn the fields behind it lay underwater. How does the author develop the event?

(1) Ida Karsh built a school library from nothing. (2) A library is a room kept for lending books. (3) In one week she gathered 900 books from neighbors. (4) By spring, 60 students borrowed daily. Which sentence illustrates sentence 1?

An article's first paragraph says quiet hours are times when a library bars talking. Its last paragraph adds: sixth grader Jo Park says, "I finally finish my reading there." What does the last paragraph do?

Passage: "Hydroponics is growing plants in water instead of soil. At Marrow Middle School, students raise lettuce in tubs of water on a shelf." The second sentence illustrates the definition with an example.

Passage: "Wind turbines need steady wind. Ridge Hollow gets it nearly every day, so nine turbines now stand along its crest." The second sentence introduces wind turbines to the reader for the first time.

(1) Beekeeper Tomas Ferrer is patient. (2) He once waited four hours beside a hive to watch one queen emerge. (3) He keeps 12 hives. (4) Bees live in colonies. Which sentence illustrates sentence 1?

(1) Rangers at Pell Canyon watch for spalling. (2) Spalling is the flaking of rock from a cliff face. (3) Last May a slab spalled onto the trail. (4) The trail closed for a week. Which sentence supplies the definition the others rely on?

A profile of chemist Nadia Oyelaran opens: "She keeps a jar of failed samples on her desk." The rest of the article explains how she learns from mistakes. What does that first sentence do?

Ferry rides to Culver Island are popular. The line is long every Saturday. Last summer the ferry carried 41,000 riders, twice the number it carried five years earlier. What does the third sentence do?

Pond ice at Rell Lake formed a month late this year. Warm autumn nights kept the water above freezing well into December. How does the author develop the event in the first sentence?

(1) School gardens teach math. (2) Students in Hale's class measure beds and figure areas. (3) Gardens are a place where math gets taught. (4) A garden is a planted plot. Which sentence adds support instead of restating sentence 1?

An article begins: "Rosa Denby was 14 when she drew her first map of the Tarn Caves." Everything after it describes her mapping career. How does the author introduce Denby?

Deep-sea fish can make their own light. The lanternfish carries rows of glowing spots along its belly. The hatchetfish does the same and can dim its spots to match the water above. What does the last sentence add?

(1) Corrie Bell started a repair cafe. (2) On its first day, six people fixed lamps. (3) Three years on, it has mended 4,000 items and trained 30 volunteers. (4) A repair cafe is a place to fix things. Which sentence shows how far the idea has grown?