填空题

The use of fire improved early man’s life in many ways. (36) made his food more (37) . Smoking and (38) food made it possible for him to keep (39) longer. He could improve his (40) tools and weapons by (41) their points over a (42) . Camp fires or flaming torches could (43) away wild animals.
Fire is so important in our human life and supplies us something that could make our life more and more comfortable and easier. The most essential one is that, fire protected man from the cold. Without fire, man could only live in warm regions. But with fire, man could move north. In the coldest winter, man could stay warm in heated shelters. (44) . Later he learned to make glass and to work with metals.
Step by step, soon man learned that water could be boiled and that food could be cooked in boiling water. (45) . Steam machinery was important to the Industrial Revolution. (46) .
Fire produces steam in electricity generating plants. The steam turns a turbine which makes electricity, which gives light.
Until right now, we could not live without fire. Imagine, what should we do if fire had disappeared from the earth And how could we live here without fire And our humans will be died out We should think, about this hypothesis.