单项选择题 A seed planted in the sensitive lining of an oyster begins a perpetual coating process that forms a pearl.()

单项选择题 The anhinga is a black water bird that frequents the perimeters of the everglades.()

单项选择题 By 1929, two years after the start of the "talkies", motion picture theaters in the United States were attracting 100 million patrons every week.()