Question

ÔĶÁÀí½â ¡¡¡¡What will power your house in the future? Nuclear, wind, or solar power? According to scientists at the Massachusetts Institute of Technology(MIT)in the US, it might be leaves£­but man-made ones£® ¡¡¡¡Natural leaves are able to change sunlight and water into energy£®It is known as photosynthesis(¹âºÏ×÷ÓÃ)£®Now researchers have found a way to copy this seemingly simple process£® ¡¡¡¡The man-made leaf developed by Daniel Nocera and his partners at MIT can be seen as a special chip with catalysts(´ß»¯¼Á)£®Similar to natural leaves, it can split water into hydrogen and oxygen when put into a bucket of water£®The hydrogen and oxygen gases are then stored in a fuel cell(µç³Ø), which uses those two materials to produce electricity£® ¡¡¡¡A man-made leaf is not a new idea£®The first man-made leaf was invented in 1997 but was too expensive and changeable for practical use£®The new leaf, on the contrary, is made of cheap materials, easy to use and highly stable£®In laboratory studies, Nocera showed that a man-made leaf prototype(Ô­ÐÍ)could operate continuously for at least 45 hours without a drop in activity£® ¡¡¡¡The wonderful improvements come from Nocera¡¯s recent discovery of several powerful, new, inexpensive catalysts£®These catalysts make the energy change inside the leaf more efficient with water and sunlight£®Right now, the new leaf is about 10 times more efficient at carrying out photosynthesis than a natural one£®Besides, the machine can run in whatever water is available; that is, it doesn¡¯t need pure water£®This is important for some countries that don¡¯t have enough pure water£® ¡¡¡¡With the goal to ¡°make each home its own power station¡± and ¡°giving energy to the poor¡±, scientists believe that the new machine could be widely used in developing countries, especially in India and rural China£® (1) What will give power to our house in the future, according to MIT? [¡¡¡¡] A£® Man-made leaves£® B£® Nuclear£® C£® Solar power£® D£® Wind£® (2) Which of the following orders correctly shows how the man-made leaf is used to produce electricity? a£®man-made leaves split water into hydrogen and oxygen b£®the hydrogen and oxygen gases are stored in a fuel cell c£®the man-made leaves are put in water d£®the fuel cell uses hydrogen and oxygen to produce electricity [¡¡¡¡] A£® cbad£® B£® bcad£® C£® cabd£® D£® cadb£® (3) What does the underlined ¡°stable¡± in the 4th paragraph mean? [¡¡¡¡] A£® Secure£® B£® Powerful£® C£® Unnatural£® D£® Unchangeable£® (4) The aim of the scientists at MIT in developing the new man-made leaves is to ________£® [¡¡¡¡] A£® build up more power stations in the world B£® provide cheaper energy for developing countries C£® offer people in developing countries access to pure water D£® gain a deeper understanding of the photosynthesis process

Answer 1

´ð°¸£º1£®A;2£®C;3£®D;4£®B;