听力原文：    

Have you ever heard of the Vikings? They were sea travellers from Norway. More than a thousand years ago, they made three important geographical discoveries.
(19) The Vikings' first major discovery occurred in the ninth century. A man called Naddod was on his way from Norway to the Faroe Islands, north of England, when his ship was caught in a storm. The storm blew the ship west for several days. When the weather cleared, Naddod found himself on the coast of a new land. Later, Viking travellers named it Iceland.
In 982, a Viking called Eric the Red sailed west in search of new land. (20) Five hundred miles west of Iceland, he and his men reached an icy rocky mass of land. They sailed around it until they reached the western side. Here, they found some green areas, so they named the island Greenland.
Then, in 1001, the Vikings made their most important discovery. The son of Eric the Red, named Leif Ericson, had heard rumors about land west of Greenland. He sailed west and soon found it. He and his men landed in three places. They called the first one Helluland, which means land of flat stones. The Vikings then sailed south and made their second landing. They named this place Markland. The third landing was at a place they called Vinland. Leif Ericson and his men were the first Europeans to walk on the shores of North America, almost 500 years earlier than Columbus.
Questions 19 to 21 are based on the passage you have just heard.
19. What do we learn about the Vikings?
20. What does the passage say about Greenland?
21. What does the speaker mainly talk about?

解析：短文中提到，维京人的第一个重大发现发生在 9 世纪。一个名叫 Naddod 的人要从挪威到英格兰北部的法罗群岛(Faroe Islands)，但他的船遇到了暴风雨，被吹向了西 方并行驶了几天，等天气晴朗之后，他们发现自己到了一片新陆地，之后维京人将其命名为 Iceland。因此答案为 C)。

短文中提到，Eric the Red 和他的船 员们在 Iceland 以西 500 里发现了一块结满了冰且到处都是岩石的陆地，他们绕着这块陆地 航行抵达了它的西面，在这里他们发现了一些绿地，因此将它命名为 Greenland。因此答案 为 D)。

短文从简单介绍维京人开始，引出 了他们的三大重要地理发现，全篇以这三大发现展开描述。从短文中不难得出，维京人的三 大发现均与海洋、航行和发现新陆地有关，因此可以概括为海洋探索，答案为 A)。