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.

Comic strips(连环漫画) are popular cartoons found in newspapers and magazines around the world. If you can think up funny dialogues, you are well on your way to becoming a successful comic strip writer. If you're also good at drawing, it will be much better!

Develop your characters(角色). Develop your characters and practise drawing them in different situations. Make sure that each has its personality, so that it's easy to tell who is who.

Make a quick sketch(素描) of your strip. When you have decided what is going to happen, work out how many panels you will need, and exactly what will be described in each panel. Stop in where the text will go, and what the characters will be doing. Use a ruler and a pencil to draw the squares. Use the pencil to draw in your images. Draw the speech bubbles, characters and any background of the scenes. Correct until you are pleased with your drawings.

Add the text. Many cartoonists just do this with a pen, but you might want to start with a pencil until you feel confident in your lettering abilities(能力).Make sure your text is very easy to read.

Ink (给……上墨) over the final lines of your squares, text and images. Be careful not to use the wet ink. When the ink is completely dry, run an eraser over your comic to clean up the paper and remove any remaining pencil marks.

References(参考词汇):

make rules to .../ be good for.../ follow the rules/ be strict with...

No rules, no standards.(没有规矩,不成方圆。)

Liu Yaxuan is totally a homebody. Every weekend, this 14-year-old student from Tsinghua High School watches popular TV dramas and plays with her mobile phone. She hates playing outdoor sports."It's too tiring,"she said.

She is not alone. In recent years, more and more Chinese teenagers are becoming homebodies. A 2013 survey of kids aged 2 to 14 showed about half of them spend less than one hour doing outdoor activities every day.

To some extent, heavy academic pressure (学业压力) caused this situation. Hu Huilan, 12, from Shenzhen Nanshan Language School, is busy with piles of homework and extra classes on weekends."I don't want to get behind,"she said.

Even if this isn't a problem, kids still prefer indoor life. Wang Yidi, 12, from Anhui No. 50 Middle School, often reads Harry Potter, listens to music and surfs the Internet at home."I can do so many things I like at home rather than hang out in smoggy weather,"she said.

But this causes bad health conditions. Chinese teenagers' physical conditions have been dropping for about 28 years, reported a newspaper last year.

The situation for teenagers should be changed. They should spend their free time outdoors even if it just means going to the park or reading a book under the tree. Nice weather, little homework and rich outdoor activities enable them to do that. It helps them stay energetic.

I'm Laura，a robot（机器人）. I can tidy rooms. Say"Clean！" to me and I can do it. 

Look! A computer and some books are on the desk. A blue schoolbag, a basketball and a box are under the desk. What can you see on the bed? A white phone. A notebook, two pencils and a pen are on it too. "Clean！"It's time to do my job（工作）. 

Now look! The books are in the bookcase, and the basketball is in the box. The phone is on the desk, but you can't see it. It is behind the schoolbag. In the schoolbag are the school things——the pen, the pencils and the notebook. 

Do you like the tidy room? I can help you.