[填空题]Before humans came on the scene, the world changed only slowly. The climate warmed and cooled, new plants and animals evolved (进化) and became extinct in their turn, and sea levels rose and fell over periods of thousands, if not millions, of years. But during the last two thousand years there have been very great changes. Forests have disappeared, river courses have been changed, and large areas of natural vegetation have turned into farmland and cities. There are serious problems for the survival of the human race.
The Greenhouse Effect
It may be cold outside, but on a sunny day it can be hot in a greenhouse. Some of the gases in the Earth’s atmosphere act like the glass in a greenhouse. Radiant heat from the Sun can pass through them to warm the Earth below. But the ground also loses heat by radiation (辐射). The "’greenhouse gases" send some of this heat back towards the Earth’s surface and help to keep it warm. However, by burning fuels

[填空题]Before humans came on the scene, the world changed only slowly. The climate warmed and cooled, new plants and animals evolved (进化) and became extinct in their turn, and sea levels rose and fell over periods of thousands, if not millions, of years. But during the last two thousand years there have been very great changes. Forests have disappeared, river courses have been changed, and large areas of natural vegetation have turned into farmland and cities. There are serious problems for the survival of the human race.
The Greenhouse Effect
It may be cold outside, but on a sunny day it can be hot in a greenhouse. Some of the gases in the Earth’s atmosphere act like the glass in a greenhouse. Radiant heat from the Sun can pass through them to warm the Earth below. But the ground also loses heat by radiation (辐射). The "’greenhouse gases" send some of this heat back towards the Earth’s surface and help to keep it warm. However, by burning fuels

[填空题]The World Trade Organization came into being in 1995. It is the successor (后继) to the General Agreement (协议) on Tariffs (关税) and Trade (GATT) established in the wake of (作为……的后果) the Second World War.
The multilateral (多边的) trading system was developed through a series of trade negotiations or rounds. The first rounds dealt mainly with tariff reductions but later negotiations (谈判) included other areas such as anti-dumping (反倾销) and non-tariff measures. The latest round, the 1986-1994 Uruguay Round, led to the WTO’s creation.
The negotiations did not end there. Some continued after the end of the Uruguay Round. In February 1997 agreement was reached on telecommunications (电信) services, with 69 governments agreeing to wide-ranging liberation measures that went beyond those agreed in Uruguay Round.
In the same year 40 governments concluded (缔结) negotiations for tariff-free trade in information technology products, and 70 members concluded a financial services deal covering