We know that trees are useful in our everyday life. They   1  us many things, such as wood, oxygen, rubber, medicines and many other things. They can  2  tell us a lot about our climate. The following are the reasons. If you   3   a tree, you can see that it has many rings. Most trees grow one new ring   4   year. Because of the reason, we know   5   a tree is. A tree over a hundred years old means that it has more than a hundred   6 . When the climate is dry or very cold, the trees do not grow very much and their rings are usually   7  . 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   8   changed suddenly. If we look at the rings on this tree, we can learn about the   9   for a hundred years. We can see  10   our climate is changing today.

A．tell B．ask C．give D．get

A．not B．too C．to D．also

A．cut across B．climb up C．walk past D．look at

A．every B．many C．the first D．from

A．how big B．how long C．how old D．how much

A．trees B．leaves C．people D．rings

A．big B．thick C．small D．thin

A．climate B．trees C．rings D．animals

A．people B．things C．climate D．life

A．how B．why C．when D．while