单项选择题A．There are too many underdeveloped countries in the world.B．Underdeveloped countries have low level of industrial development.C．Different governments have different views on the question.D．Even developed countries have complex problems.

单项选择题A．To correct a common misunderstanding about grasshoppers.B．To help explain how well grasshoppers can jump.C．To compare the size of grasshopper with that of other insects.D．To show how quickly grasshoppers respond to danger.