Passage 4 Questions 16 to 20 are based on the following passage. 　As those people on board the Mayflower settled on the Atlantic coast in 1620, they did not have to wait for roads to be built to receive passengers and produce from the other parts of the world or to send out their produce in exchange. Safe harbors—Boston, New York, Savannah—opened on ready-made highways to the whole world. The Spacious holds of ships that brought settlers could send out furs and com and rice and tobacco. An elegant London-made coach could be delivered directly to George Washington's dock at Mount Vernon on the Potomac River. 　The English who settled the thirteen American colonies were not the first Europeans to start colonies in America. Adventurers from Spain and Portugal, France and the Netherlands, along with others, had long been competing for the treasures of faraway places. A century before the Puritans came to New England, the bold Hernando Cortes, with only two hundred men, conquered the armed hordes （群）of the Aztec empire. In two years （1519-21） he had made Mexico a colony of Spain. Ten years later, Francisco Pizarro, a Spanish who enjoyed adventures and sword-fighting but could not even write his name, overcame the grand Inca empire and added Peru to the realm of the Spanish king. These Spanish conquerors were as ruthless and as courageous as any who would ever set foot on the Americas. They aimed to convert the Indians to Christianity and brought friars （修道士）to help them. But they were better at robbing than converting. They lived and died for gold and glory. They had no desire to settle down with their families as hardworking farmers. 　In 1620, when the sober William Bradford and the prudent （谨慎的）John Winthrop came to “New” England, they had another idea. They came not for gold and glory but to build homes for themselves, their children, and their grandchildren. They aimed to make a “city upon a hill” for all the world to admire. Theirs was not a violent adventure of conquest but a long-lasting tale of building. They were a bit kinder to the Indians than the Spanish conquerors had been. One of them, John Eliot, set a friendly example and even translated the Bible into the Algonquian Indian language. The Indians in New England were few in number and had no riches of gold or silver to tempt the newcomers. But they had much to teach the colonists—how to survive in the wilderness, how to hunt, and what would grow. The English colonists planted themselves and put down roots in the New World.What does “to convert the Indians to Christianity” mean in Paragraph 2?