B．To protect the exhibit from water damage.

　　C．To time how long visitors are in the room.

　　D．To count the number of visitors in the room.

　　解析：选A　推理判断题。根据第二段第二句"With a tracking system that senses movement and stops the rain wherever visitors move, it does just that."可推知，这个追踪系统能够保证游客不被雨水淋湿。故选A。

　　3．What must you do when visiting the Rain Room?

　　A．Wear a raincoat.

　　B．Wear dark clothing.

　　C．Leave your camera outside.

　　D．Pass through within 10 minutes.

　　解析：选D　细节理解题。根据表格中的最后一句"For the convenience of all guests, visits are limited to 10 minutes."可知，游客必须在10分钟之内参观完。故选D。

　　B

　　The amount of fish caught worldwide is much larger than has been reported. And that could mean serious problems for the environment and nations that depend on fisheries (渔业). A new estimate shows that it is 32 million tons higher than countries have been reporting yearly.

　　The same report notes that the world's fish catch has been declining since the late 1990s. Countries report their industrial catches to the United Nations Food and Agriculture Organization. But they do not report other kinds of fishing. This includes the catches of small commercial fisheries, which are called artisanal fisheries, and fishing for recreation and individual food.

　　Daniel Pauly at the University of British Columbia in Canada led the study. He noted that a huge amount of some catches is thrown away. "For example, shrimp trawlers (拖网渔船) keep only the shrimp and the fish that they catch - often eight to ten times as much as the shrimp - gets thrown away."

　　Pauly told VOA that better estimates of the actual global catch will help ensure there will be enough fish in the future. "But our figures suggest that since 1996 a rapid decrease is happening. And if you project this forward you end up in a few decades having much less catch, literally no catch. So that is potentially dangerous."

　　Researchers also found ways the world's fisheries are changing. They found that fishing fleets of larger nations are catching fish in the waters of developing countries more and more.

Pauly said he was surprised by the amount of fishing done by foreign fleets in competition with local fishers. "In West Africa, the figure that was most astonishing is the enormous role of foreign fishing - of European and Asian vessels fishing legally or illegally and competing against local fishermen. On the other hand for the US, Australia and some developing countries, such as