Do you want to know something about the history of weather？ Don't look at the sky． Don't look for old weather reports． Looking at tree rings is more important． Correct weather reports date back only one century， but some trees can provide an exact record of the weather even further back． It is natural that a tree would grow best in a climate with plenty of sunlight and rainfall． It is also expected that little sunlight or rainfall would limit the growth of a tree． The change from a favorable to an unfavorable climate can be determined by reading the pattern of rings in a tree trunk． To find out the weather of ten years ago，count the rings of a tree trunk from the outside to the inside． If the tenth ring is far from the other rings， then it is certain that plenty of sunny and rainy weather occurred． If the rings are close together， then the climate was bad for the tree． Studying tree rings is important not only for the history of weather， but also for the history of man． In a region of New Mexico you can find only sand--no trees and no people． However， many centuries ago a large population lived there． They left suddenly． Why？ A scientist studied patterns of dead tree rings which had grown there． He decided that the people had to leave because they had cut down all the trees． Trees were necessary to make fires and buildings． So， after the people destroyed the trees， they had to move． In this instance studying tree rings uncovered an exciting fact about the history of man． (1) It is understood that in a favorable climate ______ ．

Do you want to know something about the history of weather？ Don't look at the sky． Don't look for old weather reports． Looking at tree rings is more important． Correct weather reports date back only one century， but some trees can provide an exact record of the weather even further back． It is natural that a tree would grow best in a climate with plenty of sunlight and rainfall． It is also expected that little sunlight or rainfall would limit the growth of a tree． The change from a favorable to an unfavorable climate can be determined by reading the pattern of rings in a tree trunk． To find out the weather of ten years ago，count the rings of a tree trunk from the outside to the inside． If the tenth ring is far from the other rings， then it is certain that plenty of sunny and rainy weather occurred． If the rings are close together， then the climate was bad for the tree． Studying tree rings is important not only for the history of weather， but also for the history of man． In a region of New Mexico you can find only sand--no trees and no people． However， many centuries ago a large population lived there． They left suddenly． Why？ A scientist studied patterns of dead tree rings which had grown there． He decided that the people had to leave because they had cut down all the trees． Trees were necessary to make fires and buildings． So， after the people destroyed the trees， they had to move． In this instance studying tree rings uncovered an exciting fact about the history of man． (1) It is understood that in a favorable climate ______ ． A. tree rings grow close together B. tree rings grow far apart C. trees in New Mexico will grow big and tall D. people can cut down most of the trees in New Mexico (2) Why did ancient people usually live where there were plenty of trees？ ______ A. Trees provided them with shades． B. Trees indicated plenty of sunlight and rainfall． C. Trees were materials for cooking and building houses． D. Trees provided them with fruit and food． (3) Scientists are interested in studying tree rings because they can tell ______ ． A. a lot about what happened in history B. whether a particular tree was healthy or not C. whether people took good care of the trees or not D. how old the trees were (4) By studying the dead tree rings in Mexico the scientist found out ______ ． A. where the people had to go B. what the people had to eat C. how the people left D. why the people had to leave (5) The people had to leave the region of New Mexico because ______ ． A. they had cut down all the trees B. there were many trees there C. they had no water D. bad weather stopped the growth of trees