We know that trees are useful in our everyday life. They 86 us many things, such as wood, oxygen, rubber, medicines and many other things. They can 87 tell us a lot about our climate(气候) . The following are the reasons(理由) . If you 88 a tree, you can see that it has many rings(年轮). Most trees grow one new ring 89 year. Because of this reason, we know 90 a tree is. A tree over a hundred years old means that it has more than a hundred 91 . When the climate is dry or very cold, the trees do not grow very much and their rings are usually 92 . When it is wet and warm, the rings are much thicker. If the rings are suddenly very thin or suddenly very thick, this means that the 93 changed suddenly. If we look at the rings on this tree, we can learn about the 94 for a hundred years. We can see 95 our climate is changing today. 86. A. tell B. ask C. give D. get 87. A. not B. too C. to D. also 88. A. cut across B. climb up C. walk past D. look at 89. A. every B. many C. the first D. from 90. A. how big B. how long C. how old D. how much 91. A. trees B. leaves C. people D. rings 92. A. big B. thick C. small D. thin 93. A. climate B. trees C. rings D. animal 94. A. people B. things C. climate D. life 95. A. how B. why C. when D. while Do you know the Olympic Games? The Olympic Games are held every four years. Many players 78 all over the world take part in the Olympic Games. The old Olympic Games began around the year 776 BC (公元前) in Greece(希腊) and the modern games came from the 79 ones. Many of the sports were the same as they are now, but women were not allowed to take part in the games. The Olympic Games stopped for a long ...