(A) He was James Oliver s assistant.

　　(B) He was born in Europe.

　　(C) He was opposed to scientific agriculture.

　　(D) He spent his own money to promote his invention.

　　9. The word "it" in line 12 refers to

　　(A) scientific agriculture

　　(B) James Oliver s invention

　　(C) the cast-iron plow

　　(D) Charles Newbold s fortune

　　10. Why did farmers reject Newbold s plow?

　　(A) Their horses were frightened by it.

　　(B) They preferred lighter tools.

　　(C) It was too expensive.

　　(D) They thought it would ruin the land.