Although April did not bring us the rains we all hoped for, and although the Central Valley doesn’t generally experience the sound and lightning that can go with those rains, it’s still important for parents to be able to answer the youthful questions about thunder and lightning.
The reason these two wonders of nature are so difficult for many adults to explain to children is that they are not very well understood by adults themselves. For example, did you know that the lightning we see flashing down to the earth from a cloud is actually flashing up to a cloud from the earth? Our eyes trick us into thinking we see a downward motion when it’s actually the other way around. But then, if we believed only what we think and we see, we’d still insist that the sun rises in the morning and sets at night.
Most lightning flashes take place inside a cloud, and only a relative few can be seen jumping between two clouds or between earth and a cloud. But, with about 2,000 thunderstorms taking place above the earth every minute of the day and night, there’s enough activity to produce about 100 lightning strikes on earth every second.
Parents can use thunder and lightning to help their children learn more about the world around them. When children understand that the light of the lightning flashing reaches their eyes almost at the same moment, but the sound of the thunder takes about 5 seconds to travel just one mile, they can begin to time the interval (间隔) between the flash and the crash to learn how lose they were to the actual spark (闪光).
【小题1】According to the author, in the area of the Central Valley____.

Life gets noisier every day and very few people can be free from noise of some sort or another. It doesn’t matter where you live—in the middle of a modern city, or a faraway village—the chances that you will be disturbed by jet aero planes, transistor radios, oil-powered engines, etc. are almost everywhere.We seem to be getting used to noise, too. Some people feel quite lonely without background music while they are working.
Scientific tests have shown that total silence can be very frightening experience for human beings. However, some people enjoy listening to pop music which is very loud, and this can do harm to their eardrums(耳鼓).The noise level in some disco is far above the usual safety level for heavy industrial areas.
One recent report about noise and concentration(专心) suggested that although a lot of people say that any noise disturbs their concentration, what really affects their ability to concentrate is a change in the level of noise. It goes on to say that a background noise, which doesn’t change too much (music, for example) may even help people to concentrate.
【小题1】The best title for this passage is __________.

Shedding tears(流泪) is a natural way of making us feel more comfortable．When our eyes are made uncomfortable by some small pieces of pollution, or when we are cutting onions, or when we are exhausted(精疲力竭; 疲劳) and have “red-eyes” from overwork and late hours, tears form in our eyes to clean and refresh them．
Tears are also a sign of strong emotion．We cry when we are sad and we cry when we are happy．
And tears seem to be uniquely (惟独) human．We know that animals also experience emotion ——fear, pleasure, loneliness——but they do not shed (流) tears．From this, we can conclude that tears are closely related to the emotional and biological make-up(结构；组成) of the human species．
Biologically speaking, tears are actually drops of saline fluid, which is a little bit salty, produced by a gland (腺) in the body．Because salt is an important component, tears may actually constitute the most conclusive evidence that the human animal is the end product of a long evolutionary process that began in the sea．
And it is clear that, in addition to (除了) the emotional benefits (好处), the shedding of tears has a specific biological function as well．Through tears, we can eliminate from our body certain chemicals which build up in response to stress and create a chemical imbalance(不平衡) in the body．Crying actually makes us feel better by correcting that imbalance and making us feel good again．And thus the emotional and biological functions of tears merge (合并) into one and make us even more “human” than we would otherwise be．
60、According to the passage, human beings may have originated (起源于) in_______．
A. the sea                B. the salt      C. chemicals    D. animals
61、Which of the following is NOT a function of tears?
A. Biological   B. Emotional    C. Political           D. Chemical
62、The underlined word “eliminate” probably mean_______．
A. add            B. produce      C. replace   D. remove
63、Which of the following is the best title of the passage?
A. Tears are a sign of strong emotion．
B. Tears are always making us feel more comfortable．
C. Tears are uniquely human．
D. Tears have certain biological function．

The Internet is not perfect. There are many problems with it.
The Internet is not organized. There is no one in charge of the Internet. It is sometimes difficult to find what you are looking for. It is also easy to get the wrong information on the “Net”.
Some businessmen cheat people on the Internet. Internet thieves can steal credit card numbers. Some advertisers send spam to e-mail boxes. E-mail boxes are often filled with these unwanted advertisements.
Illegal businesses can operate on the Internet. These businesses sell X-rated materials, cigarettes and alcohol to teenagers.
The Internet has websites with information about making bombs, breaking the law and terrorism.
Criminals can fool people, especially children, in chat rooms. They can spread poisonous information and attack new members.
The Internet is the greatest advance in communication since human emerged. But it can also like a dark alley in a dangerous part of town. Parents need to set parental controls on their children when they use the Internet. This will keep some of the bad material away from their children.
The Internet can be dangerous to computers, too. Some people who have evil intentions enjoy causing problems for other people they don’t even know. They create computer viruses. A computer can get virus by downloading a program that has a virus in it. Some virus come by e-mail.
A virus can destroy the data a person has saved in computer files. A virus can cause a computer to crash. A virus can also reproduce itself! It can send copies of itself to everyone on a person’s e-mail address list. Then these people’s will have the same problems and can’t work normally!
【小题1】Why can illegal businesses operate on the Internet?

The term “multitasking” originally referred to a computer's ability to carry out several tasks at one time. For many people, multitasking has become a way of life and even a key to success. In fact, some excellent mental aerobic exercises (大脑训练) involve engaging the brain in two or more challenging activities at a time. Although checking e-mail while talking on a phone and reading the newspaper may be second nature for some people, many times multitasking can make us less productive, rather than more. And studies show that too much multitasking can lead to increased stress, anxiety and memory loss.
In order to multitask, the brain uses an area known as the prefrontal cortex (前额叶脑皮层). Brain scans of volunteers performing multiple tasks together show that as they shift from task to task, this front part of the brain actually takes a moment of rest between tasks. You may have experienced a prefrontal cortex “moment of rest” yourself if you've ever dialed (拨电话) a phone number and suddenly forgotten who you called when the line is answered. What probably occurred is that between the dialing and the answering, your mind shifted to another thought or task, and then took that “moment” to come back. Research has also shown that for many volunteers, job efficiency (效率) declines while multitasking, as compared to when they perform only one task at a time.
Multitasking is easiest when at least one of the tasks is habitual, or requires little thought. Most people don' t find it difficult to eat and read the newspaper at the same time. However, when two or more attention-requiring tasks are attempted at one time, people sometimes make mistakes.
We often don't remember things as well when we're trying to manage several details at the same time. Without mental focus, we may not pay enough attention to new information coming in, so it never makes it into our memory stores. That is one of the main reasons we forget people's names—even sometimes right after they have introduced themselves. Multitasking can also affect our relationships. If someone checks their e-mail while on the phone with a friend, they may come off as absent-minded or disinterested. It can also cause that person to miss or overlook key information being passed on to them.
1. Why are some mental aerobic exercises designed to engage people in multitasking?
A. To make them more productive.                
B. To reduce their stress and anxiety.
C. To develop their communication Skills.         
D. To help them perform daily tasks more easily.
2. According to Paragraph 2, why may a person suddenly forget who he has called?
A. He may have his prefrontal cortex temporarily damaged.    
B. He is probably interrupted by another task.
C. He is probably not very familiar with the person he has called.    
D. He may need a rest between dialing and speaking.
3. People tend to make mistakes when       .
A. they perform several challenging tasks at a time 
B. new messages are processed one after another    
C. their relationships with others are affected       
D. the tasks require little thought
4. What is the main idea of the passage?
A. Multitasking has become a way of life.
B. Multitasking often leads to efficiency decline.
C. Multitasking exercises need to be improved.
D. Multitasking enables people to remember things better.