31. What does the passage mainly discuss? (A) The explanation of an interesting phenomenon (B) Miracles in modern science (C) Procedures in scientific investigation (D) The differences between biology and physics.

30. Which of the following statements is supported by the passage? (A) Tin cans and iceboxes helped to make many foods more widely available. (B) Commercial ice factories were developed by railroad owners (C) Most farmers in the United States raised only fruits and vegetables. (D) People who lived in cities demanded home delivery of foods.

31. What does the passage mainly discuss? (A) The explanation of an interesting phenomenon (B) Miracles in modern science (C) Procedures in scientific investigation (D) The differences between biology and physics.

其他試題

31. What does the passage mainly discuss?
(A) The explanation of an interesting phenomenon
(B) Miracles in modern science
(C) Procedures in scientific investigation
(D) The differences between biology and physics.