阅读理解。 You can find out many things about a tree by studying its rings. Each year, from top to bottom, a tree grows a new layer (层) of wood around itself. If you cut across a tree trunk or branches, you would see that these layers of wood look like rings. By counting tree rings, you can tell how old the tree is. If you count ten rings, for example, the tree is ten years old. Looking at the picture shown above, you can see that each tree ring has a dark part and a light part. The light part wood grows in the spring, the dark part wood in winter. Look also, that some rings in the picture are wide and others are narrow (窄). Trees grow aide rings during the years when they get a lot of water and sun-light. By examining tree rings, you can tell what the weather may was like many years ago. Giant sequoia (红杉) trees, such as the one in the photo above, grow in north-western California. Some of these sequoias have more than 3000 tree rings. Can you guess how old such a tree would be? 1. According to the story, a tree ring is a ______. [     ] A: branch B: layer of wood C: giant sequoia D: ten years old 2. A tree ring is added to a tree ______. [     ] A: every ten years B: every year C: every 3000 years D: every two years 3. The light part of a tree ring ______. [     ] A: gets dark in the winter B: tells the tree's age C: grows in the spring D: gets light every year 4. From the story, you can tell that ______. [     ] A: all tree rings look the same B: most trees do not grow tree rings C: tree rings add to the tree's width D: most of the trees grow rings 5. Look at the drawing above. If this were a slice (片) from a tree trunk, how old would the tree be? [     ] A: Five years old. B: five months old. C: Six years old. D: Ten years old.