ElectricBackpack
Lawrence C. Rome and his colleagues from the University of Pennsylvania in Philadelphia2 and the Marine Biological Laboratory in WoodsHole3，Mass.4，have invented a backpack that makes electricity from energyproduced while its wearer walks. In military actions，search-and-rescueoperations，and scientific field studies，people rely increasingly on cellphones，global positioning system 5 receivers，night-vision goggles，andother battery powered devices to get around and do their work. The backpackselectricity- generating feature could dramatically reduce the amount of awearers load now devoted to spare batteries，report Rome and his colleagues inthe Sept.9 Science6.
Unexpectedly，tests showedthat wearers of the new backpack alter their gaits in response to the packsoscillations，so that they carry loads more comfortably and with less effortthan they do ordinary backpacks. Because of that surprising advantage，Rome plans to commercialize both electric and non-electric versionsof the backpack.
词汇:5bAkpAkwCt p
receivern.接收机 gaitn.步态，步法7Csi5leiFEnp
springn.弹簧 commercializev.商业化5vE:tikEl 7maunti5niEp
rotaryadj.旋转的
1. Backpacks are convenient because
B they can hold as many things as you want to carry.
D you do not have to carry things withyou.
and his colleagues?
B It can be used as cellphones，GPS in the military actions or field studies.
D It is light and easy to carry.
A a small stream of water flowing naturally from theearth.
C the act or an instance of jumping or leaping.
being pushed.
A To make the backpackmore comfortable for the wearer.
C To test the advantage of the backpack.
5. What is implied in if you do get oneeventually，just make sure to took both
A You will be too excited to watch the traffic.
C It is notpossible for you to get such a backpack.
答案与题解：
2.A第二段的第一句说，Lawrence C.Rome及其同事们发明的这种背包，当背着背包走路时，会有电能产生;该段最后一句告诉我们，背包的这种性能可减少背包的重量，因为不必携带备用电池。
4.B 第四段最后一句的意思是：Rome计划将这种背包商业化，即推向市场。A、C、D在文中均未提到。D的意思是为背包做广告。