填空题

In 1847 the United States Post Office Department adopted the idea of a (36)____stamp, much to the objection of those who did not like to pay (37)____. Besides, the stamp covered only delivery to the post office and did not include carrying it to a (38)____address. It is no (39)____that, during the years that followed, private letter-carrying and (40)____businesses developed. As a result, the government postal service lost (41)____to private competition. Finally, in 1863, Congress provided that the government should pay the mail (42)___for delivering mail to private addresses, and that there should be no (43)____charge for that delivery. But this delivery service was (44)____________. As of 1890, of the 75 million people in the United States, (45) ____________. (46) ____________.