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Science & Health

Numbers keep us safe and healthy. Builders use special numbers like 3.14 (π) to make strong bridges that won't fall down. Doctors use numbers like 37℃ (normal body temperature) and 60-100 beats per minute (normal heartbeat) to check health.

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Numbers tell us about people. Did you know that Asia has around 4.8 billion people? That's more than half of all people on Earth! Leaders use these numbers to decide how many schools to build. In bad times, numbers help decide how much food or medicine is needed. Stores even use numbers to know which products sell well.

Everyday Uses

We see numbers every day. When baking a cake, you need twice as much flour as sugar. At stores, a 20% discount means you can pay less money. On the road, signs like "60 km/h" tell drivers the maximum speed. Dates also use numbers, like "June 26th".

There are also some fun facts about numbers. People think differently about some numbers. In China, people believe that the number 8 means good fortune. Meanwhile, in some Western countries, people think 13 is unlucky.

        Numbers help us describe everything—from small things to huge stars. They are the world's special language.

Clouds are floating (漂浮) water drops. They are made of small water drops. Each drop is made of many water molecules (分子). They stay together around a piece of dust. How2 are cloud drops? A shoebox of clouds might3 millions of cloud drops.

Clouds are4. They look light and soft, but they hold a lot of water. The water in an average (普通的) cotton-ball cloud may have a5 as much as that of a group of elephants.

Do you dream of walking on a cloud? It would probably be very6 and wet. You would even have no comfortable7 to sit down. But weather balloons found insects inside clouds as high as 20 miles above the earth. The wind blows most of the insects into clouds. Butterflies were once found at 10,000 feet (英尺).

Clouds don't last. They are always8. When the wind blows them, they will change their9. Will the shapes stay long? Some big clouds can last around all day. But some small soft clouds often last 10 minutes. So take a look at the cloud before it10. What does that cloud look like?

get home earlier, he didn't rest on his way.

The teacher us not be late tomorrow.

The plane take off the rain stopped.

, millions of people it.

it is rainy or windy, I will be right here for you.

A perfect vacation your wise resolution and action.

We need the courage to in the face of difficulties.

I need to than others before the competition.

I am not good at drawing, but I enter the competition.