M iss Evans 1 physics in a London school. L ast month she was explaining to one of her 2 about sound, and she decided to test them to see how successful she had been 3 . She said to them, “ Now, I have a sister in Washington. If I was calling her 4 , and at the same time you were 20 meters away, and listened to me from 5 of the street, who would 6 what I said earlier, my sister or you and 7 ? ” A clever boy at once answered, “ Your sister, Miss Evens. I t is because electricity travels faster than 8 . ” “ That ’ s very good. ” Miss Evans answered; but then one of the girls put up her hand, and Miss Evans said, “ Yes, Betty? ” “I disagree, ” Betty said. “ Your sister would hear you earlier 9 when it ’ s eleven o ’ clock here, it ’ s 10 six o ’ clock in Washington. ”(2007)