45
D) danger from hunters
23. Why do grey squirrels emigrate less frequently now than they used to?
A) Most of them have already moved south.
B) Most of them are impeded by the current of the Ohio river.
C) There are now fewer natural enemies in the squirrels' habitats.
D) There is now less forest land in which squirrels are concentrated.
24. According to the passage, the squirrel emigrations have caused problems for people because
of
A) damage to homes
B) loss of farm produce
C) disruption of river traffic
D) harm to children
Twenty thousand years ago, the Earth was held in thrill by relentlessly probing fingers of ice
that drew power from frigid strongholds in the north and crept south-westward to bury forests,
fields, and mountains. Landscapes that were violated by the slowly moving glaciers would
carry the scars of this advance far into the future. Temperatures plummeted, and land surfaces
in many parts of the world were depressed by the unrelenting weight of the thrusting ice. At the
same time, so much water was drawn from the oceans to form these gargantuan glaciers that sea
levels around the world fell by three hundred and fifty feet, and large areas of the continental
shelf became dry land. This period of the Earth's history has come to be called the Ice Age. In
all, about eleven million square miles of land were covered with ice. The Ice Age terminated
about fourteen thousand years ago when the ice sheets began to retreat. It took about seven
thousand years for the ice to retreat to its present level.
1.Which of the following would be the best title for the passage ?
A) The Frigid Strongholds of the North.
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