[填空题]Obtaining Drinking Water from Air Humidity Not a plant to be seen, the desert ground is too dry. But the air contains water, and research scientists have found a _____ (51) of obtaining drinking water from air humidity. The system is based completely on renewable energy and is therefore autonomous. Cracks permeate the dried-out desert ground and the landscape bears testimony to the lack of water. But even here, where there are no lakes, rivers or groundwater, considerable quantities of water are stored in the air. In the Negev desert in Israel, for example, annual average relative air humidity is 64 percent — in every cubic meter of air there are 11.5 milliliters of water. German research scientists have found a way of converting this air humidity autonomously into drinkable water. “The process we have developed is based exclusively on renewable energy sources _____ (52) thermal solar collectors and photovoltaic cells, _____ (53) makes this method completely energy-autonomous. It w
A. A． suddenly
B．continuously
C．typically
D．seriously

[填空题]Obtaining Drinking Water from Air Humidity Not a plant to be seen, the desert ground is too dry. But the air contains water, and research scientists have found a _____ (51) of obtaining drinking water from air humidity. The system is based completely on renewable energy and is therefore autonomous. Cracks permeate the dried-out desert ground and the landscape bears testimony to the lack of water. But even here, where there are no lakes, rivers or groundwater, considerable quantities of water are stored in the air. In the Negev desert in Israel, for example, annual average relative air humidity is 64 percent — in every cubic meter of air there are 11.5 milliliters of water. German research scientists have found a way of converting this air humidity autonomously into drinkable water. “The process we have developed is based exclusively on renewable energy sources _____ (52) thermal solar collectors and photovoltaic cells, _____ (53) makes this method completely energy-autonomous. It w
A. A． path
B．road
C．channel
D．way

[填空题]Removing water from underground may cause earthquakes.

[单项选择]The concept of obtaining fresh water from icebergs that are towed to populated areas and arid regions of the world was once treated as a joke more appropriate to cartoons than real life. But now it is being considered quite seriously by many nations, especially since scientists have warned that the human race will outgrow its fresh water supply faster than it runs out of food. Glaciers are a possible source of fresh water that has been overlooked until recently. Three-quarters of the Earth’s fresh water supply is still tied up in glacial ice, a reservoir of untapped fresh water so immense that it could sustain all the rivers of the world for 1,000 years. Floating on the oceans every year are 7,659 trillion metric tons of ice encased in 10000 icebergs that break away from the polar ice caps, more than ninety percent of them from Antarctica. Huge glaciers that stretch over the shallow continental shelf give birth to icebergs throughout the year. Icebergs are not like
A. The movement of glaciers.
B. Icebergs as a source of water.
C. Future water shortages.
D. The future of the world’s rivers.