Part I
Professor: All right, folks, let’s continue our discussion of alternative energy sources and move on to what’s probably the most well-known alternative energy source, uh, solar energy. The Sun basically provides Earth with a virtually unlimited source of energy everyday but the problem has always been how do we tap this source of energy? Can anyone think of why it’s so difficult to make use of solar energy?
Student: Because it's hard to gather it?
Professor: That’s exactly it! Solar energy is everywhere but it’s also quite diffused. And the thing is the dream of solar energy is not a new one, humanity has been trying to use the Sun’s light as a reliable source of energy for centuries. And, uh, around the beginning of the twentieth century, there were actually some primitive solar water heaters on the consumer market, but they didn’t sell very well. Any of you want to guess why?
大约在二十世纪初，消费市场上其实还有一些简单原始的太阳能热水器，但卖得并不好。
1. alternative|ɔ:lˈtɜ:nətɪv|
adj. an alternative plan or offer is different from the one that you already have, and can be done or used instead 备选的；备用的；其他的
E.g.: They had a right to seek alternative employment.
他们有权另谋高就。
2. virtually |ˈvɜ:tʃuəli|
adv. almost or very nearly, so that any slight difference is not important 几乎；差不多；事实上；实际上
E.g.: He virtually admitted he was guilty.
他实际上已承认自己有罪。
3. tap |tæp|
verb. to make use of a source of energy, knowledge, etc. that already exists 利用，开发，发掘（已有的资源、知识等）
E.g.: We need to tap the expertise of the people we already have.
我们需要利用我们现有人员的专业知识。
4. diffuse|dɪˈfju:s|
verb. to make light shine less brightly by spreading it in many directions （使光）发散，漫射，漫散
E.g.: The moon was fuller than the night before, but the light was diffused by cloud.
月亮比头一天晚上更圆，但因云层遮掩而月光朦胧。
Part II
Student: Well, there were other energy choices like oil and natural gas, right?
Professor: Yeah! And for better or for worse, we chose to go down that path as a society. When you consider economic factors, it’s easy to see why. But then in the 1970s, there was an interest in solar energy again. Why do you think that happened?
Student: Because oil and natural gas were...err...became scarce?
Professor: Well, not exactly. The amount of oil and natural gas in the Earth was still plentiful, but there were other reasons. Uh, it’s a political thing really and I’m not gonna get into that now. So what happened in the 1970s was: oil and natural gas became very expensive very quickly. And that spurred people to start looking into alternative forms of energy, solar energy probably being the most popular.
无论好坏，我们作为一个社会选择了那条路。
1. for better or for worse
used to say that sth cannot be changed, whether the result is good or bad 不论好坏；不管是福是祸；不管怎样
E.g.: I married you for better or worse, knowing all about these problems.
这些问题我都知道，不管怎样我还是嫁给了你。
2. scarce |skeəs|
adj. if sth is scarce , there is not enough of it and it is only available in small quantities 缺乏的；不足的；稀少的
E.g.: Food was becoming scarce.
食物越来越紧缺。
3. get into
to become involved in sth; to start sth 参与，开始（某事）
E.g.: I got into conversation with an Italian student.
我与一位意大利学生谈了起来。
4. spur |spɜ:(r)|
verb. to encourage sb to do sth or to encourage them to try harder to achieve sth 鞭策；激励；刺激；鼓舞
E.g.: It's the money that spurs these fishermen to risk a long ocean journey in their flimsy boats.
是金钱驱使这些渔民驾着破旧小船冒险出海远航。
Part III
But then in the 80s, this trend reversed itself when price of oil and natural gas went down. All right, let’s shift our focus now to some of the technologies that have been invented to overcome the problem of gathering diffused solar energy.
The most basic solution is simply to carefully place windows in a building so that the Sun shines into the building and then it’s absorbed and converted into heat. Can anyone think of where this is most commonly used?
Student: Greenhouses.
Professor: Yep, greenhouses where plants are kept warm and provided with sunlight because the walls of the building are made entirely of glass. But we do also have more complex systems that are used for space heating and they fall into two categories, passive and active heating systems.
最基本的解决方案就是在建筑物上仔细地安排窗户的位置，以便阳光可以照射到建筑物里，然后将其吸收并转化为热量。
1. reverse|rɪˈvɜ:rs|
verb. to change sth completely so that it is the opposite of what it was before 颠倒；彻底转变；使完全相反
E.g.: The government has failed to reverse the economic decline.
政府未能扭转经济滑坡的趋势。
2. overcome|ˌoʊvərˈkʌm|
verb. to succeed in dealing with or controlling a problem that has been preventing you from achieving sth 克服；解决
E.g.: The two parties managed to overcome their differences on the issue.
两个政党设法弥合了在这个问题上的分歧。
3. greenhouse |ˈgri:nhaʊs|
noun.ˈa building with glass sides and a glass roof for growing plants in 温室；暖房
E.g.: Carbon dioxide is the largest contributor to the greenhouse effect.
二氧化碳太多是道致温室效应的最主要原因。
4. fall into
to be able to be divided into sth 可以分为；能够分成
E.g.: My talk falls naturally into three parts.
我的谈话可以自然分成三个部分。
5. passive |ˈpæsɪv|
adj.ˈaccepting what happens or what people do without trying to change anything or oppose them 消极的；被动的
E.g.: He played a passive role in the relationship.
他在他们的关系中处于被动地位。
active |ˈæktɪv|
adj.ˈactive is used to emphasize that someone is taking action in order to achieve something, rather than just hoping for it or achieving it in an indirect way 积极的；主动的
E.g.: Companies need to take active steps to increase exports.
各公司需要采取积极措施增加出口。
Part IV
Passive systems take advantage of the location or design of a house. For example, solar energy is gathered through large glass panels facing the Sun. The heat is then stored in water-filled tanks or concrete. No mechanical devices are used in passive heating systems. They operate with little or no mechanical assistance.
With active systems, on the other hand, you collect the solar energy at one location and then you use pumps and fans to move heat from the collectors through a plumbing system to a tank, where it can be used to heat a home or to just provide hot water.
Student: Excuse me, professor, but I’ve got to ask, how can solar energy work at night or on cloudy days?
Professor: That’s, well, that is a really good question. As a matter of fact, science is still working on it, uh, trying to find ways in enhancing energy storage techniques, so that the coming of night or cloudy days really wouldn’t matter. That is the biggest drawback of solar energy, the problem of what do you do in cases where the sun’s light is weak or virtually non-present. So, the storage of solar energy, lots of solar energy is really an important aspect.
其实这个问题科学还在研究，试图找到加强能量储存技术的办法，那样的话黑夜或者阴天就真的无所谓了。
1. panel |ˈpænl|
noun. a square or rectangular piece of wood, glass or metal that forms part of a larger surface such as a door or wall （门、墙等上面的）嵌板，镶板，方格板块
E.g.: One of the glass panels in the front door was cracked.
前门的一块方玻璃破裂了。
2. mechanical |məˈkænɪkl|
adj. a mechanical device has parts that move when it is working, often using power from an engine or from electricity 机械的;机动的
E.g.: The breakdown was due to a mechanical failure.
抛锚是机械故障造成的。
3. plumbing |ˈplʌmɪŋ|
noun. the system of pipes, etc. that supply water to a building （建筑物的）管路系统，自来水管道，水暖设备
E.g.: The electrics and the plumbing were sound.
电路和水暖设备都完好无损。
4. enhance |ɪnˈhɑ:ns|
verb. to increase or further improve the good quality, value or status of sb/sth 提高；增强；增进
E.g.: Large paintings can enhance the feeling of space in small rooms.
大型油画可以增加小房间的宽敞感。
5. drawback |ˈdrɔ:bæk|
noun. a disadvantage or problem that makes sth a less attractive idea 缺点；不利条件
E.g.: He felt the apartment's only drawback was that it was too small.
他觉得这个公寓唯一的缺点就是太小了。
Part V
Student: Does that mean that solar energy can only be used on a small scale, like heating a home?
Professor: Well, actually, there have been some attempts to build solar energy power plants. The world’s largest solar power plant is located in Kramer Junction, California. It can generate 194 megawatts of electric power, but that’s just a drop in the bucket. Right now the utility companies are interested in increasing the capacity of their Kramer Junction plant, but only time will tell if it will ever develop into a major source of power for that region, considering the economic and political factors involved.
目前，公用事业公司对增加其Kramer Junction发电厂的产能很感兴趣，但考虑到所涉及的经济和政治因素，只有时间才能证明它是否会发展成为该地区的主要电力来源。
1. scale|skeɪl|
noun. the size or extent of sth, especially when compared with sth else （尤指与其他事物相比较时的）规模，范围，程度
E.g.: On a global scale, 77% of energy is created from fossil fuels.
全球77%的能量产生自化石燃料。
2. megawatt |ˈmegəwɒt|
noun. a unit for measuring electrical power; one million watts 兆瓦，百万瓦特（电能计量单位）
E.g.: The project is designed to generate around 30 megawatts of power for the national grid.
该工程计划为国家电网发电约30兆瓦。
3. a drop in the bucket
an amount of sth that is too small or unimportant to make any real difference to a situation 沧海一粟；九牛一毛
E.g.: They need to raise thousands of dollars for this project, so our 20-dollar donation is just a drop in the bucket.
他们需要为这个项目筹集数千美元，所以我们捐赠的20美元只是杯水车薪。
4. utility |ju:ˈtɪləti|
noun. a service provided for the public, for example an electricity, water or gas supply 公用事业
E.g.: public utilities such as gas, electricity and phones
煤气、电和电话等公用事业
