Scientists have found a new kind of dinosaur in Gansu: Lanzhoumagniden. It has the biggest teeth of all plant-eating dinosaurs. One tooth is 14 cm long and 7.5 cm wide. It lived about 100 million years ago. 科学家在甘肃发现了一种新的恐龙：兰州龙。兰州龙的牙齿是食草恐龙中...