We always think that it's OK for us to leave our plants home during our vacation as plants won't scream like pets, right?

    A recent study done by a group of scientists at the Tel Aviv University has discovered that some plants will scream when they are under stress.

    The research was carried out on tomato plants and tobacco plants by cutting their stems (茎) and depriving (剥夺) them of water. A microphone was placed 10cm away from them. When their stems were cut, the plants started "screaming" between 20 and 100 kilohertz, and the scientists guess that this scream is probably meant to warn other plants nearby.

    When the tomato plants' stems were cut, 25 ultrasonic (超声的) pain sounds were recorded in an hour, and at the same time, 15 ultrasonic pain sounds were recorded from the tobacco plants. When they were deprived of water, the tomato plants recorded even more pain sounds with 35 pain sounds in an hour while the tobacco plants recorded about 11 pain sounds.

    The plants also acted differently to different kinds of stresses. For example, the tobacco plants gave out a stronger "scream" when they were deprived of water than when their stems were cut. But plants that were in no immediate (立刻的) danger gave out less than one ultrasonic sound per hour.

    The group of scientists said that plants are not as quiet as we had always thought, but in fact their voices are so high-pitched that we just can't hear them.

    Last year, another study has found out that plants feel pain when they are touched or hurt and they will give off a terrible smell.

    The summer holiday is coming. Try to take some time off from school and have fun. Here are some ideas for planning your summer holiday.

    First of all, joining a club is a good idea! You can join a music club, a sports club or an art club, it's good for your future and the teachers in the club can give you some good advice (建议). You can also make some new friends.

    Doing something good for society (社会) is also great. There are many volunteer programs(志愿者项目) for you to choose, such as looking after the____①___or the young, cleaning the streets, planting trees or keeping the traffic(交通) in order. You know that students can also make the world better.

    Did you ever live with another family? You can join in a program___②____"Meeting a New Family" .Two families exchange their children for some time so that they can learn how to get on well with others.

Summer camps are still popular today. An English summer camp can be a good one. You can not only make friends but also learn English.

    Just as a famous saying goes, a Reading is to success what water is to fish." {#blank#}1{#/blank#}

    It can open many doors and can lead you into a path to success. It's quite clear that every successful person has a good habit of reading. This is because reading is an important way to get the information required to understand something. {#blank#}2{#/blank#}

    Then, how can you develop an interest in reading? There is only one way. Let me explain this to you. If you want to learn how to ride a bike, you have to get on the bike as many times as possible until you can ride successfully. {#blank#}3{#/blank#} If you want to improve your reading, try to read as much as you can. When you finish reading your first book, take another book and do the same. If you are going out, take a magazine, a book, an article or something else to read. {#blank#}4{#/blank#}

    So, parents should help to get their children to read as early as possible. Studies have shown that reading to your unborn child is very good. {#blank#}5{#/blank#} Reading is always a wonderful time. Good books are good friends.

    Today, roller skating (滑旱冰) is easy and fun. But many years ago, it wasn't easy at all. Before 1743, people never tried skating on wheels. That changed because of a man named John Joseph Merlin. Merlin's work was making instruments. In his free time he liked to play the violin. Merlin was a man with many ideas and many dreams. People called him a dreamer.

    One day Merlin received an invitation to go to an important party. He was very pleased and a little excited. As the day of the party came near, Merlin began to think. He wanted to find a way to make a wonderful entrance at the party. Merlin had an idea. He thought that he would attract a lot of attention if he could skate into the room.

    Merlin tried different ways to make himself roll. Finally, he decided to put two wheels under each shoe. These were the first roller skate shoes. Merlin was very proud of them. He dreamed of arriving at the party and skating into the room while playing the violin. He was sure that everyone would be very surprised.

    On the night of the party Merlin rolled into the room, playing his violin. Everyone was really surprised to see him. There was just one problem. Merlin had no way to stop his roller skating. He rolled on, playing the violin. Then, with all eyes on him, Merlin hit into a huge mirror on the wall. The mirror broke into many pieces with a very loud noise. But nobody forgot Merlin's wonderful entrance after that.

Nature is amazing! Take a close look at the world of insects, and you'll discover many unbelievable things. Consider butterflies (蝴蝶), for example. They have beautiful wings and magical flying skills. On summer days, you always see them flying freely over flower gardens and wild fields.

But did you know how butterflies become the flying insects? It is one of the wonders of nature. In the beginning, the mother lays a small and colourful egg on a leaf or stem of a plant. It is hard to believe that the egg will become something completely different in a few days. It becomes a walking insect. This insect is called a caterpillar. It now has legs, eyes and a large body. A new life begins. The caterpillar can eat, walk and see. But it is still not a butterfly.

Soon, after growing big, the caterpillar makes a cover for itself. It covers itself in the nice protective blanket (保护层) and goes to sleep. This is known as the "pupa (蛹)" stage. After some time, the blanket breaks and a wet butterfly appears. It now has six legs, a mouth, eyes and wings. Shortly, the beautiful butterfly spreads (张开) its wings and flies away. After a few weeks, this butterfly lays her eggs, and the cycle (循环) begins all over again.

This is just one example of the wonders of nature. Look around the natural world, and you will learn many truly amazing things.