八年级学生甜甜喜欢摄影，今年五一放假期间，她随父母回了趟老家，一路上拍摄了不少反

“The world's oceans are slowly getting more acidic(酸的),” say scientists. The researchers from California report that the change is taking place in response to higher levels of carbon dioxide in the atmosphere.

The lowering of the waters' PH value is not great at the moment but could cause a serious threat to current ocean life if it continues, they warn. Ken Caldeira and Michael Wickett, from the Lawrence Livermore National Laboratory, report their concerns in the journal Nature. Increasing use of oil fuels means more carbon dioxide is going into the air, and most of it will eventually be absorbed by seawater. Once in the water, it reacts to form carbonic acid. Scientists believe that the oceans have already become slightly more acidic over the last century.

These researchers have tried to predict what will happen in the future by combining what we know about the history of the oceans with computer models of climate change. “This level of acidity will get much more extreme in the future if we continue releasing CO2 into the atmosphere,” said Dr Caldeira. And we predict the amount of future acidity will be greater than anything we have seen over the last several hundred million years.

However, it is not absolutely clear what that means for ocean life. Most organisms live near the surface, where the greatest PH change would be expected to occur, but deep－ocean life forms may be more sensitive to PH changes. Coral reefs and other organisms whose shells contain calcium carbonate(碳酸钙) may be particularly affected if the water's acidity levels keep going up, the team predict. They could find it much more difficult to build these structures in water with a lower PH.

In recent years some people have suggested storing carbon dioxide from power station in the deep ocean as a way of dealing with global warming. But Dr Caldeira said that such a strategy should now be re—considered. “Previously, most experts had looked at ocean absorption of carbon dioxide as a good thing——because in releasing CO2 into the atmosphere we warm the planet, and when CO2 is absorbed by the ocean, it reduces the amount of greenhouse warming.”

67. The ocean is becoming more acidic due to___________.

A. the lower water PH value                              B. the warming atmosphere

C. the higher level of CO2 in the air                   D. the increasing use of oil fuels

68. According to Dr Caldeira, ___________.

A. ocean absorption of carbon dioxide is a good thing

B. more oil fuels will be used in the near future

C. scientists may predict climate changes with computer models

D. the future situation of the amount of acidity is extremely serious

69. If the water's acidity level keeps rising, ___________.

A. ocean life whose structures contain calcium carbonate may be affected

B. the water's PH value will become higher and higher

C. organisms living near the surface are more sensitive to PH changes

D. some disastrous events will occur more often than before

70. Most experts once believed storing carbon dioxide in the ocean would reduce___________.

A. the CO2 absorbed by the ocean               B. the amount of greenhouse warming

C. the acidity of the ocean                          D. the gradual release of CO2

　　美国科学家最近发现，混凝土中加入碳纤维后其电阻会随外加应力等的变化而成比例改变。科学家们指出，利用这一特性制成的“智能混凝土”具有传感器功能，在道路和桥梁等建筑领域将具有广阔的应用前景。

　　美国布法罗大学的研究者发现，由于碳纤维比混凝土中的水泥浆具有更优异的导电性，实际上在混凝土中添加很少量的碳纤维成分，即可起到改变其电阻的作用。研究表明，混凝土中加入的短碳纤维只需占到混凝土总体积的 0.2%～0.55%，混凝土电阻就会按外加应力和压力变化而作出相应改变，而成为“智能混凝土”。

　　科举家们指出，当“智能混凝土”受外在压力等的作用发生变形后，其内部的碳纤维与水泥浆之间的接触程度会受到影响，从而导致其电阻变化。这一机制使得“智能混凝土”可充当灵敏度非常高的压力和应力探测器。“智能混凝土”在投入应用之前，可预先在实验室内通过测试而得出外加压力与混凝土电阻变化间的比例关系。这样，当汽车驶上“智能混凝土”构筑的路面时，通过测量路面电阻变化就能方便地称量出汽车的重量。利用同样的原理，甚至还可借助“智能混凝土”实验时测量桥梁的震动情况。

对于美国科学家的新发现，下面概括准确的一项是（）。

A．加入碳纤维的混凝土在建筑领域具有广泛的应用前景

B．加入碳纤维的“智能混凝土”具有传感器的功能

C．利用“加入碳纤维的混凝土”制成的“智能混凝土”具有传感器的功能

D．加入碳纤维的混凝土的电阻会随外应力等的变化而成比例改变

可作片剂水溶性润滑剂的物料有（）

A.滑石粉

B.聚乙二醇4000

C.硬脂酸镁

D.聚乙二醇6000

E.月桂醇硫酸镁

LED灯是一种冷光源，产生的热量极少，效率非常高。

下面关于沟通的目的和作用说法正确的是（）。

A、良好的沟通有助于个人和组织作出正确而准确的决策

B、沟通是润滑剂，能够更好的促进企业员工协调工作，提高执行进度

C、沟通不利于领导激励下属，建立良好的人际关系和组织气氛，提高员工士气

D、沟通是建立优秀团对和发展业务最重要的手段