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Miss Richards was a teacher at a school for boys and girls. She1 Chemistry and Physics from the lowest to the highest classes in the2 . Sometimes the new classes learned 3 , but sometimes they were very 4 , and then Miss Richards had to5 things many times.
One year, the first class had been studying Chemistry for several 6 when Miss Richards suddenly asked, "What is water? Who knows?7 up!"
There was silence for a few seconds,and Miss Richards felt sad,but then one boy 8 his hand.
"Yes,Dick?" said Miss Richards encouragingly. He was not one of the brightest children in the class,so she was9 that he could answer.
"Water is a liquid which has no10 until you wash your hands in it,Miss. Then it turns black," the boy replied with great confidence.