问题
单项选择题
产品方案需要在( )研究基础上形成。
A.主导产品
B.辅助产品
C.副产品
D.产品组合
答案
参考答案:D
产品方案需要在( )研究基础上形成。
A.主导产品
B.辅助产品
C.副产品
D.产品组合
参考答案:D
Leif Erickson reached North America around the year 1000, but the attempt to explore was started slowly. It would be five centuries __1__ other Europeans landed on that continent. Why were Europeans the ones to __2__ to the American? The Chinese and Arabs had the __3__ and technology to sail across the seas. __4__ of them tool regular voyages in the Indian Ocean and the Asian Pacific for trade. But exploration? By the mid-15th century China had followed the closed-door policy to __5__ itself from the rest of the world. The Arabs, with access to the minerals and spices (香料) of Africa and the Far East, saw no __6__ to journey into the unknown. Europe, on the other hand, needed gold and silver; its mines could not __7__ the demand for coinage (铸币). Ottoman Turks blocked the routes across the land to Asia. Only the sea held the promise of new wealth. __8__ the return of Magellan’s ships in 1522 from its voyage around the world, the belief was __9__ that the oceans were interconnected, promising the age of discovery. The English, as well as the Spanish, Portuguese and French, __10__ themselves to finding the “river of the west” through North America to the east.
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