There was a time when New York City buildings were almost all the same height.

3.Today you can see buildings of different heights that seem to touch the sky. They are called skyscrapers(摩天大楼). They shape the famous New York City skyline.

 It started about 90 years ago. It began like a race. This wasn't a race down the street or around a track(跑道). It was a race for the sky. Who was racing? Buildings were.Their builders were actually racing to build the world's tallest skyscraper.

 The race started slowly.

 First came the Woolworth Building, in 1913. It rose 792 feet(英尺) on the southern side of the city. Then the race heated up.In1930, two skyscrapers were nearing completion. The Bank of Manhattan Building was finished first. It rose up to 927 feet into the sky. Builders were then putting a round roof（屋顶）on the top of the Chrysler Building. It rose up t0 925 feet. The Bank of Manhattan, two feet taller, seemed to be the winner.

 A few weeks later, New Yorkers saw a strange sight（景象）.  The day that the Chrysler Building was to be completed, workers raised a shiny metal, spire（尖顶）through the top of the building, adding 121 feet to the building's height! At l,048 feet,the Chrysler Building was now the world's tallest.

 But the race was not over.  A year later, in 1931, the Empire State Building became the new winner.4.At l,250 feet, it was the world's tallest building.

 In 1973, even that record was broken. Builders finished the World Trade Center. At 1,368 feet high, it rose above all other buildings in New York City.

 Time goes on. As technology improves, taller buildings are being built. The race is still on.

It's getting hotter and hotter outside. Summer is already here! Summer means high temperature, more outdoor activities and all kinds of fruit and vegetables. How can we stay fit in this exciting season? Here are some good ideas:

 Eat and drink properly

 What is healthy to eat in summer? Fresh and light food. Fish can be a good choice. It can keep your body energetic and help fight against the burning sun. Colorful fruit and vegetables is another good choice. They not only please your eyes, but are full of healthy chemicals(化学物质). Tomatoes can help protect your skin against sunburn. Blueberries are good for your brain and eyes. The more color, the better!

With all those summertime activities you will be thirsty. What to drink? Water. Water has zero calories（卡路里）and is the perfect drink to stop you thirst. Try not to drink too many energy drinks, sports drinks and soda drinks which have lots of sugar and caffeine（咖啡因）in them.

 Stay active and cool

Summer is a great season to enjoy outdoor activities and play. It's also a good time to lose weight. If you are lucky enough to be near a body of water, try water sports like swimming, surfing, water skiing and so on. These sports keep you cool and active at the same time. You'll have no problem beating the heat and keeping fit as well.

 Be careful of the          

Summer allows us more chances to get outside, but it also means more possibilities to get burnt by the sunshine. If you are going outside, keep away from the sun when it's the strongest – usually between 11a.m. and 3p.m.. If you have to stay in the sun for a long time, sunscreen（防晒霜），a big hat and a long-sleeve jacket will be necessary.

Read a Timeline

Every family has a history. A timeline can show events in a family's history. A timeline is an ordered group of words and dates that shows when events happened. 

Learn the skill   

Step1 The title tells what the timeline is about. The timeline has a line divided in equal parts. Each park stands for 10 years.

Step2  Look at the first and last numbers on the timeline. The numbers are years. The events on the timeline happened between these years.

    It was a summer evening.  Rose was in the yard watching the stars with her family. Rose felt bored because all the stars were the same. As the whole family looked at the sky, Rose looked at the ground.She saw a lovely cat sitting beside her feet.  Then she gave him something to eat and called him Frank.

    That summer, Rose fed Frank every day.  But she couldn't make the decision to take him into her house.  Frank just came at about six o'clock every evening.  Rose would feed him whatever she could find.  She didn't know where he went after meals, but she knew he would always come back the next day.

Though the weather changed, their routine didn't change.  Then winter came.  In the first cold month, Frank came five times a week. During the next month, he only came every three days. By the end of the year, Rose hadn't seen Frank for two weeks.  Rose was very worried. She told her mother about it.  "Don't worry, honey," said her mum.  "I think Frank will appear again when it warms up,And when he comes, I think you can invite him to move inside." "Really? Thank you, Mum!" Rose said happily.  She was so eager to see her friend again.

    There are long rivers, and there are famous rivers. The Nile(尼罗河)is the world's longest and most famous river. It runs 6,650 kilometers. Crocodiles and hippos(河马)live in its waters. Pyramids built by ancient Egyptians rise along its banks.

    The main branch of the Nile, the White Nile, starts just above Lake Victoria, the world's second largest fresh—water lake, in east central Africa. Then it flows to the north. At Sudan's capital, another great river called the Blue Nile joins the White Nile. Together, they form one very powerful river. Then it goes through Egypt's famous Nile Valley before reaching the Mediterranean Sea.

    Ancient Egypt, the first great African civilization(文明), started along the banks of the Nile more than 5, 000 years ago. Ancient Egypt ruled the Nile Valley for thousands of years. Great pyramids and temples were built on the banks and we can still visit them today.

    Without the rich farmland along the banks of the Nile, there might be no ancient Egypt civilization. Every year, the Nile flooded its banks. The floodwaters covered the banks with a rich soil. The Nile's banks were easy to farm and produce crops.

    The Nile also made a perfect highway for boats. The river runs north, but the wind on the river blows south. To go south, boaters put up sails to catch the wind. To go north, they took the sails down. Ancient people traded along the river for hundreds of miles.