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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Notes
eaves [名]〔複数扱い〕（家の）軒;
reproduce 繁殖；

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I saw my first swallow of the year last Friday. These birds spend the winter in warm southern countries and come to Japan in the spring to build nests and reproduce . You can see their nests on walls under the eaves of houses. They are small birds with blueish-black backs, reddish-brown throats , and white breasts. They are about 17 cm long, and they have rather long tails. They fly around most of the day catching and eating insects in the air. When they aren’t flying, you can see them resting on power lines along the streets. (by Prof. Douglas Jarrell)
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