搜索
Trees are very important. They are the homes of many birds and animals. They give us food, for example fruit and nuts. People make different things from trees, for example paper.
How do you find out the age of a tree? Every year a little and new ring grows round the trunk(树干) of the tree. When you cut down the tree, you can count the number of rings in the trunk to tell the age of the tree. In 1964, a worker cut down a tree and counted 4,900 rings inside the tree.
Today the tallest tree in the world is a redwood tree in the U.S.A. It is 112 meters tall. It can live a very long life. Some redwood trees are 2,000 years old.
1．Which picture shows the “ring” here? ( )A． | B． | C． |
| A．Trees are the homes of many birds and animals. |
| B．Trees can't help clean the air. |
| C．Trees give us food, for example fruit and nuts. |
| A．Birds. | B．Paper. | C．Rings. |
| A．We cam count the number of rings in the trunk. |
| B．We can count the number of leaves in the tree. |
| C．We can count the number of nuts in the tree. |
| A．A red tree. | B．An apple tree. | C．A redwood tree. |
同类型试题
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
y = sin x， x∈R， y∈[–1，1]，周期为2π，函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x， x∈[–1，1]， y∈[–π/2，π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
