题目内容：

The geographical location of a country and its physical characteristics are very important to its development and progress. he United States is very fortunate in this respect.

First of all, it has a good climate. In almost 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 who 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 different physical characteristics. In the United States, there are wide plains and high mountains, thousands of lakes and rivets of all sizes, cool forests and hot deserts, and a coastline several thousand miles long.

The many lakes and rivers, as well as the long coastline, 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, trucks and airplanes are doing much of the work which was formerly done by ships and boats.

44．What are the principal physical characteristics of the United States？

A．Almost the same．  B．Rather various．

C．Very good for farming． D．Suitable for transportation．

45．In what respect is the United States very fortunate？

A．Geographical location．  B．Good climate．

C．Physical characteristics．       D．Both A and C．

46．Why are rivers，lakes and coastlines important to the development of the U. S. A？

A．They make the climate better．

B．They provide people with a good many opportunities of employment．

C．They provide people with good transportation and whatever they need．

D．They make the scenery of the country more beautiful and attractive．

47．What was used for transportation in the distant past in the U. S. A. ?

A．Trains．   B．Trucks．

C．Planes．   D．Ships and boats．