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One supermarket in Washington, D.C. wants to help people who are afraid of the coronavirus. It sends food to customers by robot. The robot looks like a box on wheels. It drives along the sidewalk until it comes to the house, and the customer can open it with a password that is sent from the store. In Singapore, the government is using a different kind of robot. It looks like a dog, and it walks around parks telling people not to gather together. In Japan, some restaurants have started using robots with shelves to serve food. Robots certainly are useful during this health emergency. (by Prof. Douglas Jarrell)
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(Image from https://thespoon.tech/)

Notes
the theory of relativity　相対性理論;
precise 正確な、精密な;

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Albert Einstein changed the world of physics with his ideas at the beginning of the 20th century. One of his most important ideas is called the theory of relativity. His ideas are difficult to understand, but scientists have shown that they are correct. Recently, scientists did an experiment with clocks at Tokyo Skytree. These clocks are very precise. They can measure very small differences in time. When the scientists measured time at the top of Skytree, they showed that it went faster than at the bottom of the tower. That is something that Einstein understood 100 years ago. (by Prof. Douglas Jarrel)
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