【单选题】Sharks are fish. There are about 350 species of sharks. The smallest sharks are only 12. 5 cm long. The largest, the whale shark, is the world's largest fish. It grows to about 1Sm long. Sharks are di...
【简答题】Sharks are among the oldest animals on Earth. There are hundreds of kinds of sharks. Most are about two meters long. The dogfish shark, however, is less than twenty centimeters in length. A shark has ...