In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.

Let me give you an example: Article: Homework can put you in a badmood , and that might actually be a good thing. Researchers from the University of Plymouth in England doubted whether mood might affect the way kids learn. To find out the answer, they did two experiments with children. The first experiment tested 30 kids. Someshapes were hidden inside a different, larger picture. The kids had to find the small shapes while sitting in a room with either cheerful or sad music playing in the background. To test their mood, the scientists asked the kids to point to one of five faces, from happy to sad. Children who listened to cheerful music tended to point to the smiley faces while the others pointed to the unhappy ones. The researchers found that sad kids took at least a second less to find the small shapes. They also found an average of three or four more shapes. In the second experiment, 61 children watched one of two scenes from a film. One scene was happy, and the other was sad. Just like in the first experiment, kids who saw the sad scene acted better compared to the others. The researchers guessed that feeling down makes people more likely to focus on a problem or difficult situation. Not all scientists agree with them, however. Other studies argued that maybe, that cheerful music in the first experiment distracted kids from finding shapes. While scientists work on finding out the answers, it still might be wise to choose when to do your tasks according to your mood. After eating a delicious ice cream, for example, write an essay.
Answer: whether mood affects their learning ability
The answer to this example can be: Researchers did experiments on kids in order to find out _ .
Here is why: It is clearly mentioned in the article that to the check effect of mood on children is the main purpose of the experiment.

OK. solve this:
Article: If you haven't already, you too should switch to the latest eco-friendly, energy-efficient, energy-saving LED (Light Emitting Diode) lighting. As the world becomes more focused on green issues, everyone should do their part in practicing energy efficiency, recycling, cutting down their CO2emissions and much, much more. One of the most successful campaigns that started in Australia is the now world-famous"Earth Hour". 2.2 million of Sydney's residents turned off their lights for an hour in a mass attempt to save energy. The following year, the same idea was adopted by a whole host of different cities. This is a great example of a campaign to promote eco-friendly options and energy efficiency. But while it clearly raises awareness, it is not a long-term solution to energy saving across the developed world. A long-term solution can be found in the form of switching to LED lighting rather than the traditional halogen lights found in a typical home. Put simply, LED lighting is the future of lighting. LED lamps use up only a fraction of the energy compared to that of regular lamps. They also produce a quality flicker-free light, and will last longer than a regular light with 50,000 hours being realistic. Not only are they longer lasting and more energy-efficient with no sacrifice in light quality, but they may quickly become a possible substitute for regular lamps that have been previously installed by homes and businesses. An ordinary 50 watt low-voltage halogen light on for 4 hours a day would cost $ 25 per year to run. With a life span of around 3,000 hours it will typically stop working at the two-year mark. Compared with the regular one, an LED light of 50 watts operating for the same period will cost roughly $ 6 per year to run and last 50,000 hours. That means it won't have to be replaced for 24 years! It really is a _ to switch to energy-saving LED lighting. Plus, you will be doing your bit for the environment by becoming more eco-friendly.
Answer: call on people to use less energy as much as possible
Answer:
"Earth Hour"is held in the world every year in order to _ .