Read the following passage and the unfinished sentences carefully. Then choose the best answer and circle your choice.
When springtime comes, everything begins to wake up. Many animals in the woods have been asleep all winter. Birds have been away. Under the snow, the ground has been hard and still.
Then, all at once, it is spring! The days begin to grow long. From the south the birds fly back, ready to build their nests. Animals wake up and start to look for food.
Trees grow new leaves. Plants begin to flower. Baby birds and animals are born. Farmers are busy from morning until night.
In many countries, people greet the spring with songs and dancing. Springtime is a happy time all over the world.
Many animals go to sleep in winter because ……………………
A. it is difficult for them to find food.
B. they have been awake during the other seasons.
C. it is too cold for them to look for food.
D. they don’t need to eat
