25.It can be inferred from last paragraph
that scientists ___.
A) are puzzled by the mystery of forest
pollution
B) feel relieved by the use of unleaded
gasoline
C) still consider lead pollution a
problem
D) lack sufficient means to combat bad
pollution
Passage Four
Question 26 to 30 are based on the
following passage.
Exercise is one of the few
factors with a positive role in long-term maintenance of body weight.
Unfortunately, that message has not gotten through to the average American, who
would rather try switching to “light” beer and low-calorie bread than increase
physical exertion. The Centers for Disease Control, for example, found that
fewer than one-fourth of overweight adults who were trying to shed pounds said
they were combining exercise with their diet.
In rejecting exercise, some
people may be discouraged too much by caloric-expenditure charts; for example,
one would have to briskly walk three miles just to work off 275 calories in one
delicious Danish pastry(小甜饼). Even exercise professionals concede half a point here. “Exercise
by itself is a very tough way to lose weight,” says York Onnen, program
director of the President’s Council on Physical Fitness and Sports.
Still, exercise’s supporting
role in weight reduction is vital. A study at the Boston University
Medical Center
of overweight police officers and other public employees confirmed that those
who dieted without exercise regained almost all their old weight, while those
who worked exercise into their daily routine maintained their new weight.
If you have been sedentary(极少活动的)and decide to start walking
one mile a day, the added exercise could burn an extra 100 calories daily. In a
year’s time,
assuming no increase in food intake, you could lose ten pounds. By increasing
the distance of your walks gradually and making other dietary adjustments, you
may lose even more weight.
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