单选题 The keyboard of a typewriter refers to the set of keys in it.Most typewriters have"qwerty"key-boards.The name crones from the first six letters on the board′s second line.The"qwerty"board was set up by C.L.Sholes,who was the first man to make a really good typewriter.Some letters,such as S and T,are used together a great deal in English.Sholes placed such pairs of letter far apart on his keyboard.This made it harder for typists to learn the keyboard.But it helped keep typewriters from jamming.On early machines the bars holding the letters often caught on each other when moving quickly.Sholes made the name of his machine easy to type.lie placed on the same line all the letters of the word"type"and"writer".Sholes put S and T far apart because__________.