input question: Write a multi-choice question for the following article, with the given choices and answer: Article: You stare at waterfall for a minute or two, and then shift your gaze to its surroundings. What you now see appears to drift upward. These optical illusions occur because the brain is constantly matching its model of reality to signals from the body's sensors and interpreting what must be happening--that your brain must have moved, not the other; that downward motions is now normal, so a change from it must now be perceived as upward motion. The sensors that make this magic are of two kinds. Each eye contains about 120 million rods , which provide somewhat blurry black and white vision. These are the windows of night vision; once adapted to the dark, they can detect a candle burning ten miles away. Color vision in each eye comes from six to seven million structures called cones . Under ideal conditions, every cone can "see" the entire rainbow spectrum of visible color1s, but one type of cone is most sensitive to red, another to green, a third to blue. Rods and cones send their messages pulsing an average 20 to 25 times per second along the optic nerve. We see an image for a fraction of a second longer than it actually appears. In movies, reels of still photographs are projected onto screens at 24 frames per second, tricking our eyes into seeing a continuous moving picture. Like apparent motion, color1 vision is also subject to unusual effects. When day gives way to night, twilight brings what the poet T.S. Eliot called "the violet hour." A light levels fall, the rods become progressively less responsive. Rods are most sensitive to the shorter wavelengths of blue and green, and they impart a strange vividness to the garden's blue flowers. However, look at a white shirt during the reddish light of sunset, and you'll still see it in its "true" color1--white, not red. Our eyes are constantly comparing an object against its surroundings. They therefore observe the effect of a shift in the color1 of illuminating on both, and adjust accordingly. The eyes can distinguish several million graduations of light and shade... Options: A in short wavelengths B as color1 pictures C by a ganglion cell D along the optic nerve. Answer: D along the optic nerve. Question:???
output answer: The retina send pulses to the brain _ .

Write a multi-choice question for the following article, with the given choices and answer: Article: At 4:53 pm. on January 12, United Nations aid worker Jens Kristensen was at his desk reading documents on the third floor of the Christopher Hotel, which served as UN headquarters in PortauPrince, when he felt a tremor . Four seconds later, the earthquake hit. "In a split second, I considered whether to run for the door or hide under my desk," says Kristensen, 48. "The door was closed, and I thought that maybe it was too far and I would be caught under falling debris , so I hid under the table." A bookshelf topped onto his desk, protecting him from being crushed by rubble and trapping him in a tiny pocket. "I was confined as if in a small coffin," he says. It was so dark, and it didn't matter if his eyes were open or closed. He used the light from his mobile phone to see around him. He found, among other items, a jar of instant coffee. "I had no food or water, only the coffee to suck on if I needed it." At about 6:30 am. on January 17, an oil leak silenced the building's generators, and Kristensen was able to hear muffled voices above where he was buried. "I thought, I was too tired to bang and shout. But then I realized, I had to take every chance. This could be one." So he called out. Six hours later, Kristensen saw his rescuers' faces. "It was so amazing. I felt I had received a second birthday," he recalls. Dehydration and pains but with only a bruise and a scratch, Kristensen took three days to recover. The UN lost more than 90 people in Haiti. But Kristensen says that the outpouring of love helps heal the pain: "The genuine happiness of people toward me here has been wonderful. You feel part of a larger family." Options: A read documents in the office B stay under the desk C run out of the room quickly D catch the falling debris Answer: B stay under the desk Question:
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Answer: When the earthquake struck, Jens Kristensen decided to _ .

Problem: Given the question: Write a multi-choice question for the following article, with the given choices and answer: Article: Several weeks ago, a mysterious Christmas card dropped through our mailbox. The envelope was addressed to a man named Raoul, who, I was ly certain, did not live with us. The envelope wasn't sealed, so I opened it. The inside of the card was blank. Ed, my husband, explained that the card was both from and to the newspaper deliveryman. His name was apparently Raoul, and Raoul wanted a holiday tip. We were meant to put a check inside the card and then drop the envelope in the mail. When your services are finished at 4 a.m., you can't simply hang around, like a hotel bellboy expecting a tip. You have to be direct. So I wrote a nice holiday greeting to this man who, in my imagination, fires The New York Times from his bike aimed at our front door, causing more noise with mere newsprint than most people manage with sophisticated black market fireworks. With a start, I realized that perhaps the reason for the 4 a.m. wake-up noise was not ordinary rudeness but carefully executed spite : I had not tipped Raoul in Christmas past. I honestly hadn't realized I was supposed to. This was the first time he'd used the card tactic . So I got out my checkbook. Somewhere along the line, holiday tipping went from an optional thank-you for a year of services to a Mafia-style protection racket . Several days later, I was bringing our garbage bins back when I noticed an envelope taped to one of the lids. The outside of the envelope said MICKEY. It had to be another tip request, this time from our garbage collector. Unlike Raoul, Mickey hadn't enclosed his own Christmas card from me. In a way, I appreciated the directness. "I know you don't care how merry my Christmas is, and that's fine," the gesture said. "I want $30, or I'll 'forget' to empty your garbage bin some hot summer day." I put a check in the envelope and taped it back to the bin. The next morning, Ed noticed that the envelope was gone, though the trash hadn't yet been picked up: "Someone stole Mickey's tip!" Ed was quite certain. He made me call the bank and cancel... Options: A he wanted the couple to pay for the newspaper B he forgot to write a few words on it C he used it to ask for a Christmas tip D he was afraid of asking for a tip in person Answer: C he used it to ask for a Christmas tip Question:
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The answer is:
The newspaper deliveryman put a blank card inside the envelope because _ .