如图1所示，在高楼前D点测得楼顶的仰角为30°，向高楼前进60米到C点，又测得仰角为45°，则该高楼的高度大约为（)。

A．82米
B．123米
C．163米
D．52米
E．70米

One of the questions that is coming into focus as we face growing scarcity of resources of many kinds in the world is how to divide limited resources among countries. In the international development community, the conventional wisdom has been that the 2 billion people living in poor countries could never expect to reach the standard of living that most of us in North America enjoy, simply because the world does not contain enough iron ore, protein, petroleum, and so on. At the same time, we in the United States have continued to pursue super affluence as though there were no limits on how much we could consume. We make up 6 percent of the world's people; yet we consume one-third of the world's resources.
As long as the resources we consumed each year came primarily from within our own boundaries, this was largely an internal matter. But as our resources come more and more from the outside world, "outsiders" are going to have some say over the rate at which and terms under which we consume. We will no longer be able to think in terms of "our" resources and "their" resources, but only of common resources.
As Americans consuming such a disproportionate share of the world's resources, we have to question whether or not we can continue our pursuit of super affluence in a world of scarcity. We are now reaching the point where we must carefully examine' the presumed link between our level of well-being and the level of material goods consumed. If you have only one crust of bread and get another crust of bread, your well-being is greatly enhanced. But if you have a loaf of bread, then an additional crust of bread doesn't make that much difference. In the eyes of most of the world today, Americans have their loaf of bread and are asking for still more. People elsewhere are beginning to ask why. This is the question we're going to have to answer, whether we're trying to persuade countries to step up their exports of oil to us or trying to convince them that we ought to be permitted to maintain our share of the world fish catch.
The prospect of a scarcity of, and competition for, the world's resources requires that we reexamine the way in which we relate to the rest of the world. It means we find ways of cutting back on resource consumption that is dependent on the resources and cooperation of other countries. We cannot expect people in these countries to concern themselves with our worsening energy and food shortages unless we demonstrate some concern for the hunger, illiteracy and disease that are diminishing life for them.
The writer warns Americans that ______.
A．their excessive consumption has caused world resource exhaustion
B．they are confronted with the problem of how to obtain more material goods
C．their unfair share of the world's resources should give way to proper division among countries
D．they have to discard their cars for lack of fossil fuel in the world

A．that
B．what
C．where
D．why

The police searched the building __ but failed to find out where the bomb was.
A．throughout
B．fully
C．altogether
D．thoroughly

By "common resources" （Paragraph 2), the author means that ______.
A．the resources possessed by the United States should be shared by other countries
B．Americans have the right to consume resources both from their home country and from abroad
C．it is difficult to distinguish the resources possessed by America from those possessed by other countries
D．all the resources in the world should be shared by all the countries

A．role
B．subject
C．joke
D．supplement