单项选择题
A. how people’s brains shrink B. the way of making people live longer C. the size of certain people’s brains D. why certain people aged sooner than others
A. both writers and cooks have to work long hours every day B. both are essential to life C. both are enjoyable D. both writers and cooks can earn a good living
A. Before takeoff. B. In an emergency. C. Throughout the flight. D. During landings.