The pilot whale（座头鲸）is one of the largest sea animals in the world. Some of them can be 7 meters long and 3000 kilos heavy. There are about 4000 pilot whales in the world. Most of them live in the Pacific and the Atlantic. A few of them can be seen in Bohai and other big seas in China.
In September, a tragedy happened on the west coast of Tasmania,
Australia. As many as 380 pilot whales became stranded（搁浅）and died. It may be the largest stranding happened in Australia on record, the BBC reported.
For centuries, the whales stranding happened all over the world. Why do pilot whales do this? Scientists did a lot of studies, but they say the reason about that is often unknown. Instead, they offered some different guesses.
Some scientists say the whales catch small fish for food and get stranded because they are not noticing where they are going. Others think that the earth has a geomagnetic field（地磁场）, which makes the whales change their ways of travelling into the wrong place.
There is another guess. Pilot whales travel in large groups. “If one head whale wrongly takes the whole group far away the deep sea, the others will not leave. ” said Shery Gibney, a great scientist from New Zealand. “Some will come in and try to help, they get stranded on the beach, then more will come. ”
Pilot whales can float （漂浮）in the deep water easily although they have a very large body. If they get stranded, their heavy body can slowly kill themselves. More than 90% of all the stranded whales will die, according to the NOAA of the US.
【小题1】The underlined word “tragedy” probably means something _________.| A．sad | B．unhealthy | C．exciting | D．surprising |
| A．Scientists have offered four different guesses to the stranding. |
| B．The stranding happened in Australia broke the world's record. |
| C．More than 90% of the stranded whales will lose their life. |
| D．The whales get stranded because they want to play on the beach. |
| A．where the whales stranding happens |
| B．how whales find their direction while traveling |
| C．when the whales easily get stranded |
| D．what may make the whales become stranded |
