题目

There are many kinds of tigers all over the world, and the largest tiger is Northeast Tiger. Most Northeast Tigers live in the northeast of China, like Heilongjiang Province and Jilin Province. Because there are many forests and mountains, the tigers usually like living there. In the forests and mountains, there are fewer people getting out and coming in. So the tigers are very free. They can run after each other, catch and eat some small animals, like rabbits and deer.The Northeast Tigers are different from the ordinary tigers. For example, the Northeast Tigers can swim very well, but can’t下列各组物质中，互称为同分异构体的是(     )A．水与冰B．O2与O3C．D．