5. According to the passage , one advantage of Sea island cotton was its

　　(A) abundance of seeds

　　(B) long fibers

　　(C) long growing season

　　(D) adaptability to different climates

　　6. Which of the following can be inferred from the passage about cotton production in the United States after the introduction of Whitney's cotton gin?

　　(A) More cotton came from Sea island cotton plants than before.

　　(B) More cotton came from short-staple cotton plants than before.

　　(C) Most cotton produced was sold domestically.

　　(D) Most cotton produced was exported to England.

　　7. The word "surge" in line 19 is closest in meaning to

　　(A) sharp increase

　　(B) sudden stop

　　(C) important change

　　(D) excess amount

　　8. The author mentions "wheat and wheat flour" in line 23 in order to

　　(A) show that Americans exported more agricultural products than they imported.

　　(B) show the increase in the amount of wheat products exported.

　　(C) demonstrate the importance of cotton among American export products.

　　(D) demonstrate that wheat farming was becoming more profitable.

　　9. The word "unprecedented" in line 26 is closest in meaning to

　　(A) slow

　　(B) profitable

　　(C) not seen before

　　(D) never explained

　　10. According to the passage , the Mississippi River was

　　(A) one of the boundaries of a region where new agricultural settlement took place

　　(B) a major source of water for agricultural crops

　　(C) the primary route by which agricultural crops were transported

　　(D) a main source of power for most agricultural machinery

　　參考答案：DACDB BACCA