1. Directions: Choose the proper words to complete the following sentences. Each word can be used only once. Note that there are two more words than you need.

appreciate    generation    renew balance     particularly     tragedy delicate    preserve     meaninglessly former     represent     comedy

1. （1） The life of humanity is in the face of natural crises.
3. （2） The global earthquake disasters approached the average level in years.
5. （3） While natural disasters bring , they also can bring out the best in humanity.
7. （4） There is an old Chinese proverb: One plants the trees; another gets the shade.
9. （5） If you slice a tree trunk horizontally, you can see the rings that annual growth.
11. （6） Most educated people associate their happiness with nature, so they try their best to nature.
13. （7） Stable emissions of carbon dioxide this year seem to have been caused by a decline in coal use, in rich countries.
15. （8） The earth-atmosphere energy is related to incoming energy from the Sun and outgoing energy from the Earth.
17. （9） Ecological restoration is a corrective step that involves re-establishing the natural processes that sustain and ecosystems over time.
19. （10） While many of us respect and nature, it is hard for countless others, whether through circumstance, lifestyle, or opportunity, to experience and connect with the natural world.