Have you ever wondered when dogs first became “man's best friend” and the world's favourite pet? If you have then you're not alone. When and where dogs first began living side-side with humans are questions that have stirred hot debate among scientists. There are a few hard facts that all agree on. These include that dogs were once wolves and they were the first animal to be domesticated(驯养) by humans. They came into lives some 15000 years ago, before the dawn of agriculture.

    Beyond that, there is little agreement. The earliest bones found that are unquestionable dogs and not wolves date from 14,000 years ago. However, 30,000-year-old skulls have been discovered in France and Belgium that are not pure wolf and some scientists think could be dogs.

    With such puzzling evidence, many scientists are now turning to DNA to find out when and where dogs were first domesticated. In one research project, tens of thousands of blood samples have been taken from street dogs around the world. The plan is to compare them with those of wolves. It's even possible to analyse DNA from ancient bones. Tiny pieces of the 30,000-year-old skulls mentioned earlier are currently being studied, and another DNA study has already shown that ancient dogs preserved in the Alaskan ice-fields evolved from Asian wolves, not American ones.

    Indeed, the ancient DNA may turn out to be more informative than the DNA of living dogs. Because dogs have accompanied humans around the world for thousands of years, their current distribution may tell us very little of their origins. This is why different groups of scientists believe that dogs variously originated in eastern Asia, Mongolia, Siberia, Europe or Africa.

    But why were the animals domesticated in the first place? The most recent theory is that dogs domesticated themselves, initially living in and around our ancient villages to eat any food thrown out. Today, this is a way of life still shared by three -quarters of a billion unowned dogs worldwide.

Do you dream?

    Have you ever visited some strange places in your dreams? In fact people have wondered about these strange places for long.{#blank#}1{#/blank#} However, they have been valued as necessary to a person's health and happiness.

    Historically, people thought dreams contained messages from God. It was only in the twentieth century that people started to study dreams scientifically, believing that they tell about a person's character.{#blank#}2{#/blank#} He believed that dreams allow a person to express fantasies or fears, which would be socially unacceptable in real life.

    The second theory to become popular was Carl Jung's compensation theory. Jung, a former student of Freud, said that the purpose of a dream is not to hide something, but rather to communicate it to the dreamer.{#blank#}3{#/blank#} Thus, people who think too highly of themselves may dream about falling; those who think too little of themselves dream of being heroes.

    Using more recent research, William Domhoff from the University of California found that dreaming is a mental skill that needs time to develop in humans.{#blank#}4{#/blank#} Until they reach the age of five, they can not express very well what their dreams are about. Once people become adults, there is little or no change in their dreams. The dreams of men and women differ. For instance, the characters that appear in the dreams of men are often other men, and often involve physical aggression.

    The meaning of dreams continues to be difficult to understand. {#blank#}5{#/blank#} If you dream that a loved one is going to die, do not panic. The dream may have meaning, but it does not mean that your loved one is going to die.

A. Dreams make up for what is lacking in waking life.

B. But anyway, people should not take their dreams as reality.

C. It gives scientists chances to better understand human mind.

D. They have been considered as meaningless nighttime journeys.

E. First, there was Sigmund Freud's theory.

F. They think their mind is trying to tell them something.

G. Children do not dream as much as adults.

    My friend Susan has a huge-hearted husband. He is once again on the front lines of fighting the fires in Northern CA. As a Chief Battalion leader, his job is very dangerous and his time away from his family is often for weeks at a time during "fire season".

Every time before he leaves, Ethan, Susan and each of the three teens hold one another and thoughtfully each shares the best of their traditions — each promises to do the tasks that will keep the family a well-oiled machine while Ethan is away.

    Ethan has brought back animals that lost their homes in the fires. By now, a gray rabbit, two parrots and a small group of Nubian goats have been added into the family.

    When Ethan is on duty, Susan keeps checking her cell phone for Ethan's text messages. His substantial (大量的) white facial hair is often mistaken for that of Father Christmas by children who are carried out of their burning homes by him.

    For each rescued child, a toy bear is waiting to be matched with him/her. For each adult, Ethan provides clean clothes. He finds pleasure in doing his job well. He is grateful to be often on the front line with frightened people and their poor pets.

    I am mentioning Ethan because by now the big fire has been spreading widely for a week. It has caused 55 deaths and left 500,000 people homeless. Now I am here at my school site, and the smoky air is keeping our students inside, waiting for rescue.

    Many of us love July because it's the month when nature's berries and stone fruits are in abundance. These colourful and sweet jewels form British Columbia's fields are little powerhouses of nutritional protection.

    Of the common berries, strawberries are highest in vitamin C, although, because of their seeds, raspberries contain a little more protein (蛋白质), iron and zinc (not that fruits have much protein). Blueberries are particularly high in antioxidants (抗氧化物质). The yellow and orange stone fruits such as peaches are high in the carotenoids we turn into vitamin A and which are antioxidants. As for cherries (樱桃), they are so delicious who cares? However, they are rich in vitamin C.

    When combined with berries of slices of other fruits, frozen bananas make an excellent base for thick, cooling fruit shakes and low fat "ice cream". For this purpose, select ripe bananas for freezing as they are much sweeter. Remove the skin and place them in plastic bags or containers and freeze. If you like, a squeeze of fresh lemon juice on the bananas will prevent them turning brown. Frozen bananas will last several weeks, depending on their ripeness and the temperature of the freezer.

    If you have a juicer, you can simply feed in frozen bananas and some berries or sliced fruit. Out comes a "soft-serve" creamy dessert, to be eaten right away. This makes a fun activity for a children's party; they love feeding the fruit and frozen bananas into the top of the machine and watching the ice cream come out below.

    A typical school day in the UK starts around 8:30 am. This is often even earlier elsewhere in the world, with students sitting down to their first lesson at 7:30 am in the US. The average teenager ideally needs eight to nine hours' sleep each night, but in reality a lot of teenagers struggle to get this much. A lot of the problems happen because our sleep patterns are not fixed, and they change as we grow.

    So a later school start time could help to solve this problem, by ensuring to get their eight plus hours of sleep and react properly to their body's natural rhythms(规律). There has been a general change over the past 25 years to shorten the school day. This is not at the cost of teaching time (which has remained constant) but at the cost of natural breaks, which has led to reduced lunch time and lesson breaks.

    Later start times could help teens' grades and health. This is mainly because it makes the management of children easier. Managing hundreds of children "playing" requires effective staffing. And there is always the fear that behavior worsens during breaks. So the theory goes that having them in class and strictly managed must be better.

    But this means that students barely have enough time to absorb what they were doing in maths before suddenly they are forced to study ancient history. And teaching staff also move through from one class to another, with hardly a rest or time to refocus.

    Clearly rethinking the school day could benefit everyone included. Anyway, it could also lead to better achievement in teenagers and less of a struggle for parents in the mornings. For teachers, it could also mean a less stressful day all around and what could be better than that?

A clever technologist took steamboat inventions and turned them into the first commercial steamboat service.

Although Robert Fulton did not invent the steamboat, as is commonly believed, he played an important role in making steamboat travel a reality. He was born in Pennsylvania in 1765. As a young man, he set out to make his name as a portrait painter. His career took him to Europe and into the orbit of people with the power to support him politically and financially.

Fulton entered London society after he painted Benjamin Franklin's portrait. While abroad, Fulton left the arts for a career in shipbuilding. He was interested in the recently-invented steam engine, and thought it could be used to power ships. Fulton's vision was not original; many others had entered the field, and the unfortunate inventor John Fitch had built a working steamship already. But like Henry Ford, Fulton's talent lay not in the invention but in the product's application in the marketplace.

Fulton didn't focus entirely on the steamboat. In 1804, he tested the first submarine successfully, which he had built for the British Royal Navy. His invention would make him a celebrity upon his return to the United States two years later. Fulton's partner Robert Livingston obtained an exclusive license for steamboat services on New York's Hudson River. It was time for Fulton to deliver.

To build an efficient, reliable steamboat, Fulton used a special English steam engine. The ship's bottom was flat and its stern was square. The steamboat Clermont made its debut (首次亮相) on August 17, 1807, steaming up the river from New York to Albany, and it soon entered commercial services. The hilly terrain of New York made water transport faster than land transport, and Fulton's boat — formerly known as the "North River Steamboat" — was a hit. Within five years, Fulton would be running services on six major rivers plus the Chesapeake Bay, and bring in great profits.