Grade 10 reading comprehension worksheets

1 Marta Nowak had interpreted for her mother at the bank, at the pharmacy and on the telephone with the gas company, where she once spent forty exhausting minutes persuading a recorded voice that her mother was, in fact, her mother. Compared with that ordeal, a parent-teacher conference for her eight-year-old brother should have been uncomplicated. Mr. Pruitt's third-grade classroom smelled of glue sticks and pencil shavings, and the chairs were so low that her mother sat with her knees nearly at her chin, her good leather handbag balanced on top of them like a shield.

2 "Tomek is a delight," Mr. Pruitt began, and Marta translated that with genuine pleasure. Then he opened a folder and, in the gentle, practiced voice of someone delivering unwelcome news, explained that Tomek had turned in only two of the last nine reading logs. Tomek talked constantly during lessons, and not in whispers: he swiveled around in his seat to entertain the row behind him, and twice he had been sent into the hallway to settle down. Marta heard herself summarize all of this for her mother, in Polish: Tomek was an energetic boy who occasionally forgot his homework. It was not exactly a lie; it was more like a photograph with the mess cropped out.

3 Her mother nodded politely and smoothed the strap of her handbag, and Mr. Pruitt, apparently encouraged, continued. "There's something else, though. In February we welcomed a new student from Poland, Kacper, who doesn't speak any English yet." He smiled a little ruefully, as if he were about to confess something himself. "Tomek has appointed himself Kacper's interpreter. Every time I give directions, he turns around and repeats them in Polish, so half the talking I write up is really that. Honestly, I can't decide whether to scold him or thank him." Marta sat very still, taking it in: her little brother was doing her job, at eight years old, surrounded by tiny chairs and alphabet posters, and nobody had asked him to.

4 With her face suddenly warm, she turned back to her mother and started over from the beginning. She translated the two reading logs out of nine, the jokes, the hallway, every unflattering detail, and then she described what Tomek had been doing for Kacper. Her mother listened without interrupting, the way she listened to the evening news on the Polish radio station, her expression giving nothing away. When Marta finished, her mother leaned forward and tapped the chart in the open folder, where a long row of empty boxes marched across the page.

5 "I can read a chart, Marta," she remarked in Polish. Then she turned to Mr. Pruitt and said in careful, deliberate English, "Thank you. He will do the logs, and he will help Kacper after the lesson, not during." Mr. Pruitt laughed, the first real laugh of the evening, and wrote her promise down in the margin of his notes. Out in the parking lot, her mother buttoned her coat against the wind and said, without looking at Marta, "Next time, all of it. I am his mother, not the gas company."

1 A single gram of healthy garden soil, about the weight of a paper clip, can contain billions of bacteria. Microbes, the living things too small to see without a microscope, are ubiquitous: they thrive in boiling hot springs, in Antarctic ice, in clouds, in the deepest ocean trenches and all over your skin. They include bacteria, many fungi such as yeasts and molds, and single-celled organisms called protists. For almost all of human history, however, nobody knew that they existed.

2 The first person known to have seen bacteria and other single-celled creatures was Antonie van Leeuwenhoek, a cloth merchant in Delft, in the Netherlands, who ground his own tiny lenses as a hobby. His single-lens microscopes could magnify objects more than two hundred times, far better than other microscopes of his day. In 1676 he reported to the Royal Society in London that a drop of water was crowded with tiny creatures swimming in every direction, which he called animalcules. Many readers doubted him until other scientists, using his methods, saw the creatures for themselves.

3 Seeing microbes was one thing; proving what they did was another. Around 1860, the French chemist Louis Pasteur boiled broth in glass flasks with long, curving necks. Air could reach the broth, but dust and microbes settled in the bend of the neck, and the broth stayed clear and fresh. When he tilted a flask so that the broth touched the trapped dust, it soon spoiled. Pasteur concluded that spoilage came from microbes carried in from outside, not from the broth itself. In 1876, the German doctor Robert Koch showed that a particular bacterium caused the deadly animal disease anthrax, and in 1882 he identified the bacterium that causes tuberculosis. Together, their work established the germ theory of disease: the idea that specific microbes cause specific illnesses.

4 Germ theory has saved millions of lives, but it also gave microbes a bad reputation that most of them do not deserve. Only a small fraction of known microbes cause disease. Bacteria in your intestines break down fiber that your own body cannot digest, produce vitamin K, and help train your immune system to tell friend from enemy. Bacteria living in small lumps on the roots of peas and beans turn nitrogen from the air into a form that plants can use. Tiny ocean organisms, many of them bacteria, produce roughly half of the oxygen made on Earth each year. Even some medicines come from microbes: in 1928, Alexander Fleming noticed that a mold had stopped bacteria from growing in a laboratory dish, a discovery that led to penicillin, the first widely used antibiotic.

5 Today, scientists can identify microbes by reading their DNA, even the many kinds that refuse to grow in a laboratory dish. This has overturned some long-held beliefs. For decades, textbooks claimed that bacteria in the human body outnumbered human cells ten to one. When researchers recounted carefully in 2016, they found the numbers roughly equal: about 38 trillion bacterial cells to about 30 trillion human cells. The invisible world, it turns out, is still being mapped.