（1）I {#blank#}1{#/blank#}my teeth three times yesterday.
（2）When I was a child, I {#blank#}2{#/blank#} to be a doctor.
（3）We {#blank#}3{#/blank#} our vacation last year. We stayed at a very nice hotel.
（4）Amy's grandfather{#blank#}4{#/blank#} when he was 90 years old.
（5）The concert {#blank#}5{#/blank#} at 7:30 and ended at 10:00.

    Sharks have been around for a very long time. It means that they have been on earth for thousands of years, and have changed little. A shark is a fish, but it has many {#blank#}1{#/blank#} from a fish. For example, if a shark {#blank#}2{#/blank#} swimming, it will sink(下沉).

    There are {#blank#}3{#/blank#} 200 and 250 kinds of sharks in different size. The largest can be {#blank#}4{#/blank#} long as 15 meters. Sharks feed on fish, {#blank#}5{#/blank#} sea animals, or smaller sharks. It is said that one of the most {#blank#}6{#/blank#} sharks is the Great White Shark. They have attacked(攻击) a number of people off the beaches of America. Australia, New Zealand and South Africa also have shark 0attacks. In some places there {#blank#}7{#/blank#}watchtowers on the beach to warn people about sharks in the water. {#blank#}8{#/blank#} a shark appears, a bell rings to tell people to get out of the water. Shark attack about 100 people a year in America. Perhaps the shark {#blank#}9{#/blank#}thinks that the people is a kind of sea animal, or {#blank#}10{#/blank#} good to eat.

    My wife and I were on the beach, with our children. We were{#blank#}1{#/blank#}pictures of some birds.{#blank#}2{#/blank#}I heard my daughter Lisa shouting, "Dad! A bear is right behind{#blank#}3{#/blank#}" Then I saw that small bear. It {#blank#}4{#/blank#}quietly behind us then.

    While my wife and I {#blank#}5{#/blank#}about it, it stood across me. The bear behaved abnormally (表现异常). It hit the camera, cutting it off the tripod (三脚架). The {#blank#}6{#/blank#}got  very  difficult. I was standing there -- between the bear and my family. All of us had little {#blank#}7{#/blank#} of running faster than the bear. The bear opened its mouth. I had to raise my arms {#blank#}8{#/blank#} myself. I caught its {#blank#}9{#/blank#} While I was getting ready to fight (战斗) with it, it started to rain heavily. The bear moved back towards the forest. But before {#blank#}10{#/blank#}to the forest, it bit my arm. The first time I felt afraid. I drove away quickly with my family. I didn't feel my arm hurt till I arrived home.

    Life today is much easier than it was hundreds of years ago, but it has brought new problems. One of the biggest problems is pollution. To pollute means to make things {#blank#}1{#/blank#}. Pollution comes in many forms. We see it, smell it, drink it and {#blank#}2{#/blank#} hear it.

    Man is now slowly polluting the whole {#blank#}3{#/blank#}

    Air pollution is still the most serious. It's bad for all living things in the world, {#blank#}4{#/blank#}it is not the only kind of pollution. Water pollution kills our fish and pollutes our drinking water. Noise pollution makes us {#blank#}5{#/blank#}more easily.

    Many countries are making rules to {#blank#}6{#/blank#}pollution. They stop people {#blank#}7{#/blank#}burning coal in houses and factories in the city, and from putting dirty smoke into the air. Pollution by SO₂ is now the most dangerous kind of air pollution. It is {#blank#}8{#/blank#}by heavy traffic. We are sure that if there are fewer people driving, there will be {#blank#}9{#/blank#} air pollution.

    The Earth is our home. We must take care of it. That means {#blank#}10{#/blank#}the land, water and air clean .And we must take care of the rise in pollution at the same time.