阅读理解 Text D The ecosystems of the Earth provide an array of free public services that are essential the support of civilizations. They maintain the quality of the atmosphere, provide food from the sea, manufacture and replenish soils, recycle wastes and nutrients, control the overwhelming majority of crop pests and disease vectors, and so on. People have no idea how to take over these activities satisfactorily. They do know, however, that the theory once advanced in the nineteenth century--- that the productivity of the land can be indefinitely increased by the application of capital, labor, and science --- is wrong. History has shown that once the natural life-support systems of a civilization have been sufficiently damaged, they cannot usually be repaired. The ancient deforestation and overgrazing of the Mediterranean region is a famous example. And today, a global civilization is ruining the global environment.

单选题 What is the main topic of this passage?

单选题 The word “array” in the first sentence is closeset in meaning to

单选题 The word “they” in the second sentence refers to

单选题 Which of the following could NOT be included under the “free public services” listed in the second sentence:

单选题 The word “advanced” in sentence 4 is closest in meaning to