Question IX. Fill in each numbered blank ONE suitable word. Write your answers
in the space provided.(20pts)
Solar energy is a long lasting source of energy which can be used
(1)_____anywhere. To generate solar energy, we only need solar cells and the sun!
Solar cells can easily be installed on house (2)______, so no new space is needed and
each user can quietly generate their own (3)______. Compared to other renewable
sources, they also possess many advantages. Wind and water power (4)______on

turbines which are noisy, expensive and easy to break down. Solar cells are totally
silent (5)_____ non-polluting. As they have no moving parts, they require little
maintenance and have a long lifetime.
(6)_________, solar energy also has some disadvantages. We can only generate
solar energy (7)_________daytime because the system depends on sunlight. Besides,
solar cells require large area to work effectively. The main disadvantage of solar
energy is (8)____________ it costs about twice as much as traditional sources such as
coal, oil, and gas. This is (9)___________ solar cells are expensive. Scientists are
hoping that the costs of solar cells will reduce as more and more people see the
advantages of this environmentally (10) ______source of energy.