Which of the following statements is false？
A．People know exactly how and why humans domesticated the first dogs.
B．People learned to selectively breed dogs for certain specific tasks.
C．Of all the domesticated animals, dogs seem closest to their owners.
D．Wolves raised in captivity still fall to understand human gestures:

At some later point, what did humans start to breed dogs for？
A．For looks and companionship.
B．For hunting and protection.
C．For herding livestock.
D．For fun.

听力原文：The theory once advanced in the nineteenth century—that the productivity of the land can be infinitely 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. Today, a global civilization is ruining the global environment.
The Mediterranean region is cited as an example of .
A．the ability of nature to remedy human destruction
B．the ability of people to make use of natural resources
C．the manner in which people replenish the environment
D．the effects of human abuse of natural resources

What was today's most popular breed of dog, the Labrador was originally bred for？
A．For chasing prey.
B．For herding livestock.
C．Hauling nets and retrieving fish for the fishermen.
D．For keeping accompany.

听力原文：At the Earth Summit in Johannesburg over a year ago, Israel and Jordan agreed to look into building a "Red-Dead" pipeline that would run 320 km along their rugged desert border. Dubbed the "Peace Conduit", the canal would be the biggest Israel-Jordanian joint venture since their 1994 peace treaty. Israeli officials cite the importance of cooperation with former Arab enemies as one of the main reasons they favor the Red-Dead canal over an older "Med-Dead" proposal to take water from the Mediterranean Sea, which would not involve Jordan.
Why did Israelis prefer the "Red-Dead" canal to the "Med-Dead" proposal？
A．Because they wanted to cooperate with their former Arab enemies,
B．Because the Red-Dead canal would run across the desert.
C．Because the Med-Dead canal would be much longer.
D．Because they didn't want to take water from the Mediterranean Sea.

Not until I began to work __ how difficult it was.
A．I knew
B．I did know
C．did I know