①.The sun on a spring morning shines on the
water, off bridges and boats. The blue crabs are big, and the striped bass are
bigger. On the surface, all these would probably make you think the Hudson was about as
healthy as it has been since Indian times.
② A study by the environmental group Riverkeeper examined an important indicator of the life of
any river-fish and found discouraging news. Ten of thirteen species it examined
are reducing, and one― the great and delicious shad― is at a historic low.
③ The river is getting warmer, and the heat
helps starve the water of oxygen. Power plants kill untold millions of fish
when they suck up river water to cool their machinery. Invasive species, dirty
water and fertilizer runoff and over-fishing in the ocean, where species like
shad spend much of their lives, all take their toll.
④ Striped bass are on the increase, as are
bluefish and spot-tail shiners. But with other species moving slowly
downstairs, signs point to a sicker, less stable Hudson ecosystem than many had imagined.
The report shows how little we
understand the biology of one of the country’s most historic and important
estuaries(河口，江口). It is a reminder that even
the hardest-fought conservation victories may look like the easy ones, and that
self-satisfaction can be the death of environmental progress.
Umbrella
is what we easily forget and ① behind in our daily life. When the
weather is fine, we certainly don’t think of it; only when it's raining, we’ll
carry it purposefully. But as soon as the rain stops, most likely we’ll forget ② we’ve put it. It has to wait patiently
and pitifully for its owner to claim it, ③ it’ll remain alone as a deserted
umbrella.
Once
I suddenly found my longtime used and ④ (treasure) umbrella “disappeared”. I
really got lost and regretted quite some time for my own carelessness.
Several
days later, out of my ⑤, I saw it quietly stand in a corner of the
house where I worked. I was ⑥ (extreme) glad to regain it. Looking
carefully at it, though it was so familiar to me, I found for the first time
its wooden handle had worn out, and its color had faded as a result of repeated
rain-wash for years. I had paid ⑦ attention to it all the time. I sought
for it only when I needed it.
It
sets me ⑧. Around us there are always people who give
us support in silence just like an umbrella that’s duty-bound to fend off the
rain or any wretched weather. It’s we who often
⑨ its existence. Accustomed to its service,
its care, accommodation and tolerance, we take all these as something natural,
and take it for granted. Will you think of the umbrella that protects you ⑩ ill weather when the day is warm and
sunny?
⑤It reminds us that it is difficult to gain conservation victories
and we should never be self-satisfied with the little progress we achieve in
environmental protection.
，求
的最小值，并求出取到最小值时相应
的值.
上有一点
，它的极径长比点
，求点
，阿伏加德罗常数为
，水的摩尔质量为
，在标准状况下水蒸气的摩尔体积为
，求：
是人工产生的放射性元素，
．关于
（2）在做“用油膜法估测分子的大小”实验中，油酸酒精溶
----------------------------------------（7分）
即
时，取到最小值. ------（3分）
，
，其准线方程为
．…………………（4分）
，则
，即
，则
．…………………………………………（３分）
．而点P可在第一象限或第四象限，
．………………………………………………………（３分）
（4分） （3）
（4分）
