試題詳解

51. According to the passage, which of the following statements is TRUE?
(A)The ash clouds produced by volcanic eruption sometimes turn the moon blue.
(B) People saw purple suns and red sunsets after the eruption of Mount St. Helens.
(C) The wavelength of red light will be widened if the air is filled with large particles.
(D) The Indonesian volcano Krakatora has erupted numerous times since 1883.