An aerosol (气雾剂) product, then，is just a can that has an aerosol mixture inside. With most aerosol cans, the product inside—that is，the cream，or the paint, or whatever—is mixed with a gas. Most of the time the gas that is used is a fluorohydrocarbon (碳氢氟化合物). Almost any gas could be used，,and the aerosol would still work. But fluorohydrocarbons are used because they are inert—or inactive. We feel being inactive is safer. That means they don’t have any effect on the product inside the can. To take an example, if we mix whipping cream or cheese together with a simple gas—such as oxygen--then the oxygen will immediately start to act on the product, and little by little the oxygen will ruin the product. Cheese mixed with oxygen becomes bad within a few days. That would be dangerous if it is eaten. But, by mixing the product with a fluorohydrocarbon，the product will not change and can be stored for a long time.

An aerosol (气雾剂) product, then，is just a can that has an aerosol mixture inside. With most aerosol cans, the product inside—that is，the cream，or the paint, or whatever—is mixed with a gas. Most of the time the gas that is used is a fluorohydrocarbon (碳氢氟化合物). Almost any gas could be used，,and the aerosol would still work. But fluorohydrocarbons are used because they are inert—or inactive. We feel being inactive is safer. That means they don’t have any effect on the product inside the can. To take an example, if we mix whipping cream or cheese together with a simple gas—such as oxygen--then the oxygen will immediately start to act on the product, and little by little the oxygen will ruin the product. Cheese mixed with oxygen becomes bad within a few days. That would be dangerous if it is eaten. But, by mixing the product with a fluorohydrocarbon，the product will not change and can be stored for a long time.

You are Li Yan. You were injured in a minor accident inside a supermarket. Write a letter of complaint to the manager of the supermarket. In the letter,① tell him who you are,② give details about the accident,and③ suggest how the supermarket could prevent similar accidents. (150-200 words)

Read the following paragraph and underline the topic sentence.

People disagree sharply about video games. Parents, doctors, and some media-effect researchers say the games are destructive. They accuse video games of distracting students from schoolwork, of being too violent, and of plunging the participant into an unreal world without actual person-to-person contacts. For example,Patricia Greenfield,a professor of psychology at the University of California, notes that when she asked a boy why he liked video games better than television，he answered，“On TV,if you want to make someone die,you can’t.” Defenders of the games counter that the games do have positive aspects. They note that the games help improve eye-hand-brain coordination, develop reasoning abilities, and improve perception of space. In addition, say the games' defenders, video games pave the way for players to develop positive attitudes toward computers and computer literacy skills.

A、Crowne and Marlowe (1964) developed a test to measure the need for social approval.

B、Evidently the low scorers had less need to be approved and could recognize a dull chore!

C、High scorers even stated they had learned something from the experiment.

D、Interestingly, the subjects who had high scores on the need-for-approval test claimed they enjoyed the task.

E、Just as there are differences in the type and number of Mends needed, there are also wide variations in the intensity and strength of the need to belong and be accepted by others.

F、Sound like fun?

G、They used subjects (试验对象)who have either extremely high or extremely low scores on their tests.

H、Next, the high and low scorers were asked to do a chore.

I、They were also far more enthusiastic about the scientific usefulness of the experiment than were the low scorers.

J、They were told to put twelve spools in a box, lifting only one at a time.

K、When the box was full, they had to empty it and place each spool back in the box.

Read the following paragraph and choose the best topic sentence from the four options that follow. Write the corresponding letter of your choice in the blank provided.

Many people begin their day by waiting for a bus or train. Then they may spend a few minutes waiting for an elevator to get to their offices. Moreover, the elevator may then stop at twenty floors, averaging a wait of twenty seconds each. After work, there's another wait for both an elevator and a bus or train. Most of us also spend a great deal of time waiting in the dentist’s office, in line for tickets or fast food, and on the road in barely moving traffic.

A、Many people spend a lot of time just sitting or standing around.

B、Many people do a lot of waiting during their workday.

C、Waiting is a part of many people’s lives.

D、Waiting is necessary in people’s lives.

Your choice:_______

His deepest wish is to see the hungry properly fed, the homeless adequately housed, and to treat the sick effectively.

Choose the best topic sentence from the four options below. Write the corresponding letter of your choice in the blank provided.

A、Shopping at a catalogue store isn't as satisfying as going to a regular department store.

B、The catalogue salesclerks don’t seem to know much about the products they sell.

C、How shopping at a catalogue store compares with shopping at a department store.

D、We don’t get to look at the goods before buying it.

Your choice: ________

Knowing Grandma had a weak heart, the bad news was broken to her gently by Dad.

The plainclothes men noticed a dark-haired beauty slip something into the spy’s pocket. When nobody was looking.

Shortly after the Spring Festival, Xiao Lin returned to Shanghai preparing for a job interview.