单项选择题
A. part of a historical cave system B. the biggest underground lake in the world C. listed in the Guinness Book of World Records D. the largest body of water in Tennessee
A. tell the origin of intelligence tests B. explain the basic principle of intelligence tests C. describe the changes in the content of intelligence tests D. state the development of intelligence tests
A. twins understand each other very well B. twins are slow to learn to talk C. twins are unlikely to do less well at school than other children D. there exists more communication between twins