单项选择题
A．So far, rockets with men have been to Other places. B．Rockets with men can fly to other places farther away than the moon. C．Perhaps one day rockets will be able to go to any place in space. D．A plane can fly to the moon.
A．at the beginning of the nineteenth century B．in the middle of the nineteenth century C．more than two hundred years ago D．when people first sent letters and postcards.
A．How did stamps begin t6 be used B．Why were postmen sent to get postage C．When did people first begin to use stamps D．Who was the first to think of using stamps