右侧漫画蕴含的哲理是 A．现象存在于规律之中 B．现象是客观的，规律是主观的

The United States is the world's largest consumer of energy. We use electricity, gas and oil to light and heat our buildings and run our cars. The demand for power is growing. But we may not need to build new power plants or find more oil. The best way to increase our supply of energy is to be more efficient.

Did you know that when you leave your video-game console (游戏机操纵台) on, it consumes more electricity than two refrigerators? Or that those funny-looking, twisty bulbs (灯泡) use 75％ less power than traditional light bulbs? We have the tools to save money, reduce pollution and even help our planet, simply by wasting less energy.

As President, Barack Obama plans to make energy efficiency in American a major goal. He has promised to cut 15% of all energy used by the Federal Government. In a speech, he called for 75% of government office buildings to be updated for better efficiency. He pointed out that energy-efficient buildings and homes will save consumers billions of dollars on energy bills. An “extra benefit”, he added, will be “a cleaner, safer planet.”

Gas, coal and oil are called fossil fuels. Fossil fuels have been the world's main source of energy for hundreds of years. But burning them releases dirty gases, which cause pollution.

There are two main ways to save energy. The first is to use more efficient machines. Hybrid cars use less gas. New appliances are designed to use less electricity. Today's refrigerators are three times more efficient than those before 1973. Laptop computers consume much less energy than desktop computers.

The second is to use machines more productively. According to the US Department of Energy, in the average home, 75％ of the electricity used to power electronic equipment is standby power (备用电源) . That means power flowing to plugged-in appliances whether or not they are being used.

Homeowners can avoid wasting power by pulling the plug on appliances when they are not in use. Efficiency experts argue that today's best techniques could cut US oil and gas use in half, and reduce our electricity use by three-fourths.

小题1:By referring to Obama's plan, the author mainly intended to say that _______

A．the US government office buildings have wasted the most energy

B．Obama has decided to take the lead to cut down the use of electricity

C．it is time for the US to shoulder the responsibility for a cleaner planet

D．the US is determined to improve energy efficiency in the whole America小题2:It can be inferred from the text that ________.

A．to build new power plants or find more oil is no longer useful

B．burning fossil fuels can lead to a growing demand for power

C．everyone can make a difference by wasting less energy

D．most of the electricity is wasted with appliances plugged-in小题3:What would be the best title for the text?

A．The world's largest consumer of energy

B．The world's energy efficiency movement

C．We need to find new energy

D．We have to be more energy efficient

设随机变量X服从参数为λ的指数分布，求：

在数学研究史上，比较一致地认为从古至今，数学发展经历了（）次大危机。

A、三

B、四

C、五

D、六

在系统转换的过程中，旧系统和新系统并行工作一段时间，再由新系统代替旧系统的策略称为__（1）__；在新系统全部正式运行前，一部分一部分地代替旧系统的策略称为__（2）__。

空白（1）处应选择（）

A.直接转换

B.位置转换

C.分段转换

D.并行转换

发车指示信号，昼间为高举展开的绿色信号旗靠列车方向（）。

A.上下摇动

B.转动

C.作圆形转动

D.上下缓动