My brother is very busy. He often{#blank#}1{#/blank#}     day and night.

—What do you think of this math problem?

—It's as{#blank#}2{#/blank#}  as anything.

"May I come in?" he asked{#blank#}3{#/blank#}  .

Mrs. Black doesn't allow her son {#blank#}4{#/blank#} computer games on school nights.

We should be friendly to {#blank#}5{#/blank#} . They're also members of our world.

图画、黑板、风筝等“在墙上”，是因为它们在墙的表面，故用on the wall。

门窗、钉子、洞、孔等“在墙上”，是因为它们在墙的里面，故用in the wall。

There is a picture {#blank#}1{#/blank#} and there are four holes {#blank#}2{#/blank#}.

Anna: What is the topic of your project?

Alice: About {#blank#}1{#/blank#} in our city.

Anna: It is a good topic.

Alice: The pollution is rather serious. It's said that some {#blank#}2{#/blank#} pour waste water into the river near our city.

Anna: It may pollute our water.

Alice: You're right. We should do a survey near the river and take action.

Anna: {#blank#}3{#/blank#} great your idea is!

Alice: I'll write my report and do something for it. Would you love to do it with me?

Anna: Sure! Let's work {#blank#}4{#/blank#}.

Alice: The city is our home. It is our duty to make it clean and {#blank#}5{#/blank#}.

    Life in the 2lst century is different from that in the 20th century because many changes have taken place. There are more and more people in the world and most of the lives are longer than before. Computers are much smaller, more {#blank#}1{#/blank#}and more popular. And Computer Science is one of the most important subjects {#blank#}2{#/blank#} . People work fewer hours than they did in the 20th century, and they have more free time for sports, watching TV and travelling. {#blank#}3{#/blank#} is much more convenient and easier. And more people go to {#blank#}4{#/blank#}countries for holidays. There are changes in our food, too. More land is used for building new towns and houses. Then there is less room for cows and sheep, so meat becomes more expensive. People have to eat more vegetables and fruit. {#blank#}5{#/blank#} it's good for people's health.