单选题 The traditional American Thanksgiving day celebration 21 to 1621. 22 that year a special least was prepared in Plymouth, Massachusetts. The colonists who 23 there had left England because they felt 24 of religious freedom. They came to the 25 and faced difficulties in 26 the ocean. The ship which 27 them was called Mayflower. The North Atlantic was difficult to travel. There were bad storms. They were 28 in learning to live in the new earth by the Indians who 29 the region. The puritans, 30 they were called, had much to be thankful 31 . Their religious practices were 32 longer a source of criticism by the government. They learned to 33 their farming habits to the climate and soil. 34 they selected the fourth Thursday of November for their Thanksgiving 35 , they invited their 36 , the Indians, to join them in dinner and 37 of gratitude for the new life. They recalled the group of 102 men, women and children who left 38 . They remembered their 39 who did not see the shore of Massachusetts. They 40 the 65 days journey which had tested their strength.