【推荐1】It’s 3000 years ago, and people make the things they need by hand. They use metals, such as bronze and tin, to make tools and weapons, but these metals are hard to find. A group of people called the Hittites begin ________with a unique rock called iron ore, which is easy to find and mine. They make a(n) ________: By heating this rock, they get a new metal, called iron, which they can shape into sharp knives and other tools. The Hittites see little use for iron, ________, beyond making these simple tools. Never in their wildest dreams can they imagine the ________ iron will have on the world. But it’s where the story of the ________ begins.

This early form of iron isn’t strong enough for large things like buildings. Over thousands of years, though, people learned ways to make iron stronger. They ________ their rock ovens, raising the temperature and adding different minerals to the ore. Each experiment ________ the process, as people learned to change iron into carbon steel.

Finally, in 1855, an English engineer named Henry Bessemer invented a machine that turned large amounts of iron into steel in just minutes, which is strong and can be made into nearly any ________, including frames for tall buildings. Still the first skyscraper wasn’t built for almost 30 years. Why? Nobody wanted to walk up and down all those stairs. Tall buildings need a way to elevate people and objects. Although elevators existed, they weren’t safe enough for people. Pretty soon, seeing steel cables supporting bridges led people to ________ how steel cables could make elevators safe. And with safe elevators, you could build much ________ buildings. In 1884, the Home Insurance Building, the first skyscraper, rose. It was 138 feet high — higher than any other building at that time. It had ten storeys and four elevators — a miracle at the time!

The mighty skyscraper is much more than a building, though: It’s a ________ of what we can accomplish when we just try things. Inventions come from ideas, big and small, and from people old and young. So put on your thinking caps, because the great inventions of the future ________ your ideas today!

【推荐2】Many people I know(including members of my family) feel exercise is a time-consuming and unpleasant activity. They need to change into other clothes, to frequently take a block of time out of busy lives, and to get dirty and exhausted: they find it all ________. But I’ve always________ the hard work and even the satisfaction of earning the next day’s sore muscles. And I had a slight sense of pride in knowing not only that I was helping the biological machinery that promotes health but also that I got a nice side________ of being able to eat cookies because I’d burned extra calories.

________ Or, at least, not entirely right. As science shows over and over again, our intuitive ideas of how things work often don’t ________ in the face of data and careful analysis. The benefits of exercise are a case in point. In this issue’s cover story, “The Exercise Paradox scientist Herman Pontzer describes a surprising and fascinating result of evolution: humans burn about the same number of calories regardless of ________ level. And compared with other animals, we use a lot of calories. In addition to ________ our common sense, the findings provide further insights about why our kind has been so extraordinarily successful, becoming the ________ force on the planet. By the way, to be clear, we should all ________. Regular activity does help our inner engines run right, and it has some benefits in elevating mood and improving cognition (认知). But enabling weight loss regardless of diet? Not so much.

The knowledge that we have had the capability to rule over our own world has________ the idea that we would someday also come to live on other planets. To be sure, that________ encompasses healthy amounts of romanticism, a sense of adventure and even concerns about having sufficient options to ensure our species long-term survival. ________ the “easy” problems of longer space journeys include escaping Earth’s gravity with rockets, building airtight ships with enough air to breathe, and carrying huge amounts food and water. A much harder________ is one that Hollywood never told you about: the damage to the brain done by cosmic radiation (宇宙射线)，which neuroscientist Charles L. Limoli describes in “Deep-Space Deal Breaker.” Will it prove to be the barrier to our ________ “the final frontier? One thing is certain: the human ambition means we won’t ________ trying.

【推荐1】Maybe you all know George Washington, who was _______ in chief of the Continental Army during the American Revolutionary War (1775-83) and served two _______ as the first U.S. President.

His home was on a farm near a river. There were fields and meadows (草地) around the house, and _______ many barns and storehouses that it _______ almost a little town by itself. As a child, he was lovely and listened to his parents. Unfortunately, his father died when George was _______ young. Then Mrs. Washington took _______ of the home and farm. She was very _______ of horses and had a number of them. Among them was a young horse no one had been able to _______. One day George and his friends saw this horse in a field. The other boys helped George _______ the horse and put the bridle (缰绳) on it. Then George ________ its back. The animal kicked and jumped. It tried ________ to throw its rider. At last it gave a great jump and ________ to the ground dead. The boys were very much ________ because it was Mrs. Washington’s favorite.

When the boys went home, Mrs. Washington said, “Young gentlemen, have you seen my horses? I am told my favorite has ________ to be a fine large horse.”

George said, “Your favorite is dead, madam. I ________ him.” Then he told the whole ________ .

His mother didn’t speak for a minute. Then she said, “I am ________ that my favorite horse is dead, but I am glad that my son always speaks ________.”

He always told the truth, and he ________ his father and mother. If these things had not been ________ of him as a boy, he would never have grown up to be a great man.

【推荐2】Buried deep within the cracks of an old, wooden desk, a worn-out notebook lay forgotten. Its pages, yellowed with _________, were scattered with handwritten notes and drawings, each ________ a dream or aspiration of its owner, Emily Dickinson.

Dickinson, a ________ teacher, had passed away peacefully in her sleep, leaving the notebook as one of her few _________. There were drafts of traveling to foreign places, notes about learning a new language, and even a few ________ about publishing her own book of poems in it.

One ________ sketch caught her children’s eye as they looked through the pages. It was a drawing of a small cottage ________ in the hills, surrounded by greenery and a stream. Dickinson had always dreamed of retiring to such a place, a place where she could find peace and ________.

Her children decided to fulfil her mother’s dream. They found a cottage ________ to the one in the sketch and bought it. They ________ it with the furniture and kick-knacks (小摆设) that Dickinson had treasured and turned it into a ________ to her life and her dreams.

The cottage became a place where Dickinson’s family and friends could gather and shared stories about her. It was a place where they could feel her ________ and be inspired by her firm determination. The notebook, now ________ on a small table in the cottage’s living room, remains a constant ________ of Dickinson’s dreams and aspirations. Her children hope that by keeping it there, they can honor her memory and continue to inspire others to ________ their own dreams, just as she had done.

【推荐3】My dad passed away in November last year. And it took me several months to feel “_________” in the world again. I didn’t realize it at the time, but in retrospect(回想), the_________described in this piece was an _________part of that process.

I was on a two-week tour of northern Italy, during which I visited the violin_________in the city hall of Cremona, where priceless old violins are_________. Each day, some of these violins are_________and played as a way of keeping them in their finest condition. I was_________to hear the fantastic violin “Il Cremonese”_________by Antonio Stradivari, a master of instrument making. As I sat in that simple hall, surrounded by the ancient paintings and stones, I_________myself to the strains(旋律)of the violin.

My dad also__________music and he had served in Italy during World War II. So I felt he had been with me during my whole Italian journey-and from Venice to Verona, I would catch myself wondering if he had looked at the__________beautiful hills or squares sixty-five years before.

But it was at that moment in Cremona that I__________his presence most powerfully, and that his__________and mine were intertwined(交织在一起)in the__________of the violin. And I__________that people, from newly-made__________to life-long family, __________come and go in the composition of our lives, but that once they have appeared, they never really__________. They are just like those__________. Every day, in one form or another, we take them out and play them, if just for a while. We honor them and keep them__________-as they do us, intertwined.