Passage One
　　Questions 21 to 25 are based on the following passage.
　　Electronic waste, also called e-waste has become an issue of serious concern to environmentalists as a growing number of electronic items are discarded in landfills(垃圾填埋场) every year. Many consumers are not aware that electronics like computers and cell phones actually contain toxins that can enter the soil and damage the environment.
　　Several nations have passed laws about e-waste to try and keep it out of landfills, or in landfills which are equipped to handle toxic materials. The heavy metals in e-waste pose serious environmental and health risks. While many consumers are trained to think of things like cathode ray tubes(阴极射线管) as dangerous articles that require special disposal, most do not connect cell phones, for example, with beryllium, a toxic heavy metal which can cause severe damage to the lungs. In addition to the toxins it contains, e-waste also takes a very long time to biodegrade, which means that it will be taking up landfill space for centuries.
　　The question of what to do with e-waste is a serious one. In the first world, many companies have begun to take steps to reduce the amount of e-waste they create. Companies which manufacture electronics are starting to take items back when they are no longer useful so that usable elements like copper can be safely removed and the rest of the electronics can be safely disposed of. However, a large portion of unwanted electronics in the first world is being shipped to the third world.
　　Sometimes this e-waste is shipped under the cover of humanitarian(人道主义的) reasons, arguing that old technology can still help bridge the gap between first and third world. Slow computers which are not wanted in the United States, for example, might make a big difference to someone living in Africa. However, much of this equipment actually arrives in an unusable and broken state, and people desperate for money try to harvest usable materials such as valuable metals from donated equipment. Unfortunately, most of these individuals lack training in how to handle the dangerous materials used in electronics manufacture, and expose themselves and their communities to toxic chemicals and metals.