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.

Article: We always read reports about costs of oil going up and we will think this is our most valuable material. However, water is the most valuable resource . People in the Middle East are more worried about this than oil. Maybe the next war will be about water. In the future, to control the quality and quantity , you will use different water for different usages. The water used to wash your car, water your flowers or wash your clothes doesn't need to be as clean as the water you drink. One in five people live in countries without enough fresh water and in 25 years, the number is believed to be one in every three people. Our world population is increasing. What do you suppose this will suggest for us in the future? Population control? Traditional management of the water industry has been out of date since the 1990s. When technologies develop so rapidly in the world, we have loads of information for technologies in the business world, but in the water industry we don't have any. Britain and France have already taken measures to successfully improve their water industries. All the water services in Britain have been provided by private companies since 1991. Since then, improvement has been made in the rules for their water quality and pricing. What can you do now for the future? Using water more efficiently in your house can make a great difference not only to the world but to your money. Even if you don't have to pay much now, you will when you start to pay big prices for different water usages.
Answer: the world population is growing up.
Water shortage is getting more serious because _ .

Article: Liz had been bleeding for a long time! She was my closest professional colleague and good friend at the time when we worked in an IT company. It was her first day back at work after an operation and I thought she should have taken a few more days to recover. Realizing that we couldn't stop the bleeding, we headed to the emergency room and spent hours there waiting to be seen. After the treatment, I drove her to my apartment. I had to leave her in my apartment while I dashed off to take a final exam for a very important course I was taking. Upon my return, we decided Liz was in a good enough condition to sustain a trip back from my Northern Virginia apartment to her home in Maryland. Although it was nearly midnight and we were both exhausted, we still decided to set off. Unfortunately, in a not particularly safe part of town, we heard my car make a strange noise, and then ti was shaking violently as we drove along. Quickly, I stopped the car in the road and found a tire had blown out. Not knowing how to change a tire and feeling scared, I was trying out to figure out what to do next. Liz, weak from losing all that blood all day and weighing only about eighty pounds to begin with, came out and tried to help me. I had to scream at her to get back in the car and relax. Within seconds, a taxi pulled up behind us. A huge man appeared and began walking toward us. I felt that the blood drained out of my face and I nearly fainted in fear. "Got a flat tire, girls?" he asked. "Yes," I answered in a trembling voice. In no time at all, the man changed the tire for us and rushed off back to his taxi. He refused any payment and did not even tell me his name. He would never know how badly we needed his services that particular evening. And I, with a grateful heart, will never forget his kindness.
Answer: she had an operation but didn't rest enough
The author thought that Liz was bleeding because _ .

Article: The Sieferts are the kind of environmentally conscious family who has solar panels atop their home. They use timers on their kids' showers and have planted drought-tolerant landscaping. But they feel kind of guilt. "I haven't thought about the pool as much as I probably should," said Annette Siefert. As California's drought worsens, swimming pools have become a target for those who think the classic backyard greens waste water. Some water districts have banned new pools from being filled and have limited how much water existing pools can use. But some of those agencies are walking back the rules as they make a surprising discovery: Pools aren't the water wasters some have made them out to be. Analyses by various water districts, along with scientific studies, conclude that pools and their surrounding landscapes use about the same amount of water as a lawn of the same size. Over time, pools might even use less water. With pool covers, experts say water evaporation can be cut by almost half, making pools significantly less wasteful than grass and about as efficient as drought-tolerant landscaping. Facing complaints over a recent ban on filling pools, the Santa Margarita Water District conducted its own water-use analysis. It found that pools require thousands of gallons of water to fill initially, but they use about 8,000 gallons less water than a traditional landscape after that. By the third year, the analysis found, the savings add up, and a pool's cumulative water use falls below that of a lawn. Water agencies such as the Los Angeles Department of Water and Power have come to similar conclusions. Armed with new information, Santa Margarita Water District officials will reconsider their ban next week. "We want to respect the people's rights to use their property. There are many families we know that have saved for pools," said Jonathan Volzke, spokesman for the 155,000-customer district. "But at the same time, the reality around us is that we're in the third year of a serious drought, and we don't know if we're in the third year of a three-year drought or the third year of a 10-year drought."
Answer: the water-use of their swimming pool
Annette Siefert feels guilty mainly because of _ .