单项选择题A. To find out how much air can be pumped into a plane. B. To find out how much air passengers need to breathe at certain altitudes. C. To find what would happen if the plane crashed in the water. D. To find out if there are any weak parts in the plane that would burst under pressure.
单项选择题A. The meaning of facial expressions depends on situations. B. Facial expressions can cause misunderstanding across culture. C. People from one culture may lack facial expressions because they experience less emotion. D. Facial expressions may disguise true feelings.