What is the main food of pandas? How long dose it take a bamboo to grow into big plant? Why do farmer cut bamboo trees?

Once there were lots of pandas in the mountains of Western China. Today they are becoming extinct. The reason is they cannot find enough food. Pandas eat bamboo leaves. They don't like another food. The bamboo grows very slowly. Its can take ten yeard for a bamboo to grow from a seed to a big plant. Some types of bamboo have seeds only once every 60 years. Pandas must wait many years for their food to grow. While the bamboo is growing, pandas do not have enough leaves to eat. Farmers are using more and more of the land on the mountain side to grow food for man. The farmers cut down the bamboo. Bamboo leaves become less plentiful. Pandas cannot find enough food to eat. They starve and die. China and World Wildlife Fund (WWF) are trying to save the pandas. In 1979 they began to set up special parks where pandas cna live. One such park is the Wolong Reserve in Sichuan. The Wolong Reserve has the highest number of pandas in the world. Scientists come here to study the pandas"eating and habits. By learning more about the pandas"habits, scientists can save them from extinction.
1. What is the main food of pandas?
A. Bamboo trees
B. bamboo leaves 
C. bamboo roots 
D. young bamboo trees
2. How long dose it take a bamboo to grow into big plant?
A. 60 years
B. a decade
C. a century 
D. 10 month
3. Why do farmer cut bamboo trees?
A. to get food for pandas 
B. to drive pandas away
C. to make pandas starve and die 
D. to get farmland
4. What do scientists do to save pandas from extinction?
A. they only set up parks for them
B. they put them in bamboo forest
C. they study about pandas"habits
D. they plant bamboo trees and set up parks for them