In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.

Article: Using too much water or throwing rubbish into our rivers are clear ways that humans can put our water supply in danger , but we also affect our water supply in less obvious ways. You may wonder how paving a road can lead to less useable fresh water. A major part of the water we use every day is groundwater. Groundwater does not come from lakes or rivers. It comes from underground. The more roads and parking lots we pave the less water can flow into the ground to become groundwater. Human activity is not responsible for all water shortages . Drier climates are of course more likely to have droughts than areas with more rainfall, but in any case, good management can help to make sure there is enough water to meet our basic needs. Thinking about the way we use water every day can make a big difference, too In the United States , a family of four can use 1. 5 tons of water a day! This shows how much we depend on water to live, but there's a lot we can do to lower the number. You can take steps to save water in your home. To start with use the same glass for your drinking water all day. Wash it only once a day. Run your dishwasher only when it is full . Help your parents fix any leaks in your home. You can even help to keep our water supply clean by recycling batteries instead of throwing them away.
Answer: Throwing rubbish into lakes.
Which of the following is most likely to lead to less groundwater?

Article: New picture The National Gallery now has a fine _ by the 18th century Dutch painter Jan van Os.This large picture (89.1 cm x 71cm) of flowers and fruit is painted in light bright colours on wood.It is one of the first pictures of this type in the Gallery.The picture is signed and dated 1777 and 1778.It is not unusual for a picture to be dated two years: the artist waited for particular flowers to come out in their different seasons in order to paint them.This picture was given to the Gallery by Miss Violet Churchman in memory of her sister Ida Nancy. It is now on show in Room 25. Special exhibition The exhibition "Painting in Spain During the Late 18th Century" opened in the Sunley Room on 15 March.Recently the Gallery has bought works by three Spanish painters of this period--Paret, Melendez and Francisco Bayeu, who are the focus of the exhibition.These three artists are also joined by Francisco's brother Ramon, by Antonio Gonzalez and two Italians who worked in Spain during these years--Corrado Giaquinto and Giovanni Battista Tiepolo.The exhibition runs until 31 May. Lecture news Lectures will be given along with the special exhibition every Wednesday.On 8 April, Lizzie Barker will discuss the work of Melendez, while on 15 April, Sarah Symmons will lecture on Luis Patter.On 22 and 29 April, Juliet Wilson will talk about Francisco Bayeu.On 25 April, a Saturday, Erika Langmuir will explain how artists often "tell a story" through their pictures.
Answer: Eight.
How many artists' paintings are on show at the special exhibition?

Article: If you need glasses to read this, you are among the majority of Chinese students. That's because most students in China are short-sighted which means they can only see things close up and distant things will be _ . Four-fifths of high school students wear glasses and now more and more children in primary school need glasses, too. This epidemic of poor eyesight has two very simple causes: too much time spent indoors studying and too little time spent outdoors playing. Reading and writing for hours and hours, sometimes in poorly lighted rooms, causes eyesight to weaken. But students have to do this because there is so much pressure on them to succeed in school. And because they spend so much time indoors at school and at home, they have less time to spend outdoors enjoying the sun. The sun, as a consequence, is important in developing good eyesight. Exposure to daylight releases a chemical in the eyes that prevents, or at least delays, short-sightedness. According to a study by Ian Morgan of Australian National University, Australian children and Chinese children have the same level of eyesight before they start school, but once they enter primary school, Chinese children only spend about an hour a day outside, while Australian children spend three to four hours each day in the sunshine. The result is that while about 40 percent of Chinese primary school students need glasses, only three percent of Australian children do. Wearing glasses may not seem like a big deal. For some, wearing glasses can even be an opportunity to make a fashion statement. But poor eyesight at a young age can have serious long term consequences. As you get older, your eyesight can worsen and lead to things like macular degeneration , a condition of the eyes for which there is no cure and which can eventually lead to blindness. With all that in mind, don't you think it's time to give your eyes a break? Try spending a little less time inside and go for a walk in the park, instead. It's the healthy thing to do and your eyes will thank you for it.
Answer: They should stay longer outdoors.
How should the students protect their eyesight according to the passage?