听力原文： Finland is perhaps the most beautiful and mysterious of the countries of Northern Europe. Two thirds of its surface is covered with thick forests and among them lie lakes, connected with rivers and canals. The northern part of this country is inside the Arctic Circle, where almost no trees Can grow because of its cold weather and the people use their deer for transport, clothing and food.
The Finnish history began in the Middle Ages. In about 1155, Finland Was conquered by its western neighboring Sweden. After a period of rule by Denmark in the 14th century, the Swedes won back independence and power in 1523 under their brave king, During the Napoleonic Wards (1814 -1818), Finland was passed finally from Sweden to Russia. The opportunity came in 1917, when the Russian Revolution brought foreign rule of Finland to an end. Shortly after Soviet Russia made peace with Germany, 1919 saw the founding of the Finnish Republic.
The years between the First and Second World Wars were years of progress and growing development. Finland has no coal or oil, and the nation's wealth lies in the timber (wood prepared for use in building, etc. ) from its forests, which supplies material for paper and furniture making, and in the electric power from its water.
How much of Finland's surface is covered with thick forests？

About 67%.
B. About 50%.
C. 100%.
D. 66%.