阅读短文，根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有一项为多余选项。
Thousands of years ago, people didn't live in cold places because they didn't know how to keep themselves
warm. Later they learned to make clothes. When an animal was killed, they made use of its skins to cover their
bodies.
Nature is people's good friend. It once helped people find fire, when lighting hit a forest and started a fire.
_____ The fire kept them warm, and also frightened wild animals. Soon people found the food cooked tasted
much better, so they began to use the fire to cook food.
But people still didn't know how to make a fire. When they got a fire from the forest they tried to keep it
burning.
But later they found different ways to make fire. For example, they made fire by burning wood or knocking
two pieces of stones.
Today it's easy for people to make fire because they have matches, lighters and different kinds of heaters.
A. If it went out, they had to wait for years.
B. The skins keep them warm.
C. They can make fire at any time they need.
D. People took some of this fire to their homes.
E. People didn't know how to use fire.