根据短文内容,从短文后的七个选项中选出能填入空白处的最佳选项.选项中有两项为多余选项.
Without plants, people could not live. We eat plants. 小题1: And we need plants for another reason: we need them because they are beautiful.
小题2: Imagine no flowers with their sweet smell, their beautiful colors and their lovely shapes. Imagine, when the wind blows, we’re not able to hear the leaves in the trees or watch the branches swing from side to side.
小题3: That is why we have parks full of trees and flowers. That is why people always like houses with room for some grass or a garden.
Do you talk to your plants? 小题4: Peter Tompking and Christopher Bird wrote a book called The Secret Life Of Plants, telling of an experiment in which two seeds were planted in different places. While the plants were growing, one plant was given love and hopeful ideas. The other plant was given only hopeless ideas. 小题5: Under the earth it had more and longer roots; above the earth, it had a thicker stem and more leaves. While the other one nearly stopped growing.
A．Plants get energy from the sun.
B．Do you give them love and attention?
C．After six months, the deserted plant faded away.
D．After six months, the beloved plant was bigger.E. We take in oxygen that plants make.
F. Everywhere people need beautiful plants.
G. Imagine a world with no plants.
。确定a，b的值，使等式在变换ξ=x+ay，η=x+by下简化为
。