Section B
Directions: In this section, you will hear 3 short passages. At the end of each passage, you will hear some questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A, B, C and D.
听力原文： It is very self evident that the geographical location of a country and its physical characteristics are very important to its development and progress. The United States is very fortunate in this respect.
First of all, it has a good climate. In all sections of the country it is possible to live comfortably during the whole year. It is true that in the south it sometimes gets very hot, and in the north very cold, but the people live in these regions become accustomed to the climate and never suffer very much when the weather is either very hot or very cold.
In a large country there is usually a great variety of physical characteristics. In the United States, there are wide plains and high mountains, thousands of lakes and rivers of different sizes, cool forests and hot deserts and a coastline several thousand miles long.
The many lakes and rivers, as well as the coast line have been of great importance to the development of the country, since they made possible the easy transportation of people and all the things people need. Transportation by water is still necessary and important. In modern times, however, trains, automobiles and airplanes are doing much of the work which was formerly done by ships and boats.
(27)

A. In population.
B. In the geographical location.
C. In its physical characteristics.
D. Both B and C.