IT WOULD BE MORE_________TO SWITCH THE MACHINE OFF AT NIGHT, (ECON...

35. It would be more_________to switch the machine off at night, (economy),

READING

(36-45). Choose the word or phrase (a, b, c or d) that best fits the blank space in the

following passage.

A volcano is an opening in the earth’s surface through (36)________ lava, hot gases, and

rock fragments erupt. Such an opening (37)________ when melted rock from deep within

the earth blasts through the surface. Most volcanoes are atop mountains, (38)______

cone-shaped mountains. The mountains themselves are also called volcanoes. Eruptions

of volcanic mountains are (39)________ sights. In some eruptions, huge fiery clouds rise

over the mountain, and glowing rivers of lava flow down______ (40) sides. In other

eruptions, red-hot (41)________ and cinders shoot out the mountaintop, and large chunks

of hot rock are blasted high (42)______ the air. A few eruptions are so (43)______ that

they blow the mountain apart. Some eruptions occur on volcanic islands. (44)_______

islands are the tops of volcanic mountains that have been built up from the ocean floor by

repeated eruptions. Other eruptions occur along narrow (45)________in the ocean floor.