[单项选择]After the United States bought the _______ for only $15 million, its territory almost doubled.
A. Ohio Territory
B. Gadsden Territory
C. Louisiana Territory
D. New Mexico Territory

[单项选择]The United States bought Louisiana from ______.
A. France
B. Spain
C. Britain
D. Mexico

[单项选择]The machine which we bought from the United States several years ago needed.
A. being repaired
B. to repair
C. repaired
D. to be repaired

[单项选择]After the United States became independent, the cure of more fertile lands drew steadily New Englanders into the Ohio Valley and the British colony of Upper Canada.

[单项选择]After 15 years in the United States, he has finally decided to______American citizenship.
A. concentrate on
B. apply for
C. look out for
D. appeal on

[单项选择]How many states are there in the United States


A. Thirteen.
B. Fifty.
C. Fifty one.
D. Sixty.

[单项选择]The United States is composed of fifty states, two of ______ are separated from the others by land or water.
A. them
B. that
C. which
D. those

[单项选择]

The United States government publishes guidelines for appropriate nutrient intakes These are known as the Recommended Dietary Allowances (RDAs) and are updated regularly based on new research in the science of nutrition. RDAs are suggested amounts of calories, protein, and some minerals and vitamins for an adequate diet. For other dietary substances, specific goals must await further research. However, for the U.S. population as a whole, increasing starch and fiber in our diets and reducing calories (primarily from fats, sugar, and alcohol) is sensible. These suggestions are especially appropriate for people who have other factors for chronic diseases such as family history of obesity, premature heart disease, diabetes, high blood pressure, and high blood cholesterol, or for those who use tobacco. Snacks can furnish about one-fourth of the calorie requirements among teenagers Those snacks should also furnish much of the day's allowances for protein, minerals, and vitamins. Sa
A. protein
B. fats
C. starch and fiber
D. sandwiches