小题1:B
小题2:D
小题3:B
小题4:B
小题1:细节理解题，根据文中语句“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 (电池), which uses those two materials to produce electricity, located either on top of a house or beside the house.”理解可知。
小题2:细节理解题，根据文中语句“These catalysts make the energy transformation (转换) 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 device can run in whatever water is available; that is, it doesn’t need pure water.”理解可知。
小题3:细节理解题，根据文中语句“With the goal to “make each home its own power station” and “giving energy to the poor”, scientists believe that the new application could be widely used in developing countries, especially in India and rural China.”理解可知。
小题4:理解归纳题，根据文中语句“”理解可知。
