单项选择题
A. a mouse appears B. the spotted owl ignores him C. no one answers D. barred owls appear
A. because wind and rain changed the weather B. the drop in the temperature would have effects on wind and rain C. because wind and rain did not change the weather D. the drop in the temperature would not have effects on wind and rain
A. our brains shrink as we grow old B. the front section of the brain does not shrink C. seventy-year-olds have better brains than sixty-year-olds D. brain contraction may vary among people of the same age