2014届高考英语一轮复习 Unit19 指导课时作业B卷（含解析） 北师大版.docVIP

Unit 19 B卷 一、阅读理解 A The climate secrets of the deepest part of the ocean，the Marianas Trench(壕沟)in the western Pacific Ocean，have been explored by scientists. The international team used a submersible，designed to withstand great pressure，to study the bottom of the 10.9km-deep underwater canyon.Their early results reveal that ocean trenches are acting as carbon sinks.This suggests that they play a larger role in regulating the Earth’s chemistry and climate than was thought. Although two explorers，Jacques Piccard and Don Walsh，reached the deepest part of the Marianas Trench—a point called the Challenger Deep—in 1960，no humans have been back since.And the scientific missions，including this recent visit to this deepest spot，have been carried out using unmanned underwater vehicles. Lead researcher Professor Ronnie Glud，from the University of Southern Denmark and the Scottish Association for Marine Science，said that working at more than 1,000 atmospheres of pressure was challenging，but advances in technology had made it possible. He told BBC News，“This is the first time we have been able to set down sophisticated(精密的)instruments at these depths to measure how much carbon is buried there.”The tests also helped the scientists to assess the storage of carbon at those dark depths. This is not the first time deep sea trenches have surprised scientists.Recent studies by University of Aberdeen’s Oceanlab team have revealed that marine life is much more abundant in this difficult habitat than was previously thought.In 2008，they filmed the deepest living fish ever to be caught on camera—a 17-strong shoal(鱼群)found at depths of 7.7km in the Japan Trench，and they discovered that other animals such as amphipods were present in large numbers even deeper.Dr Alan Jamieson，from Oceanlab，said the new study was helping researchers to build up a better idea of what happens in the deepest of the deep. 1．From the description of carbon sinks we learn that ______. A．they have been on the ocean f