“OK class. Count off by fives.” 【小题1】 Sometimes, breaking into small groups lasts as long as the class does. Other times, it signals the start of “group project” which means you’ll be working with a few classmates for a day, several days, or longer on an assignment.

【小题2】 Most things are done with the help or ideas of other people. Group projects are great practice for high school, college, and real life, when you have a job that requires working with others. Right now, group projects can be fun and they often allow you to do a bigger, more interesting project than you could do alone. 【小题3】

Group projects also give you a chance to get to know kids you might not know or talk with — maybe the quiet kid in the third row, or the boy who lived down the street when you were in kindergarten. 【小题4】 For example, working on a deadline staying organized, or being patient. And if you’re a little nervous talking in front of a group, a joint project can help you become more comfortable with it.

【小题5】 If so, you’ll know your whole group is rooting for (给……加油) you!

An earthquake is one of the most common natural disasters． It may cause great damage． So it is wise to learn some simple safety tips to protect yourself or your family members．

Fragile items， like those made of glass should usually be placed on a lower surface， near the ground instead of placing them on cupboards higher up． Never place them near your bed， sofas and other furniture where you would be sitting or lying down． When there is a strong movement，these pieces will fall on the floor directly and not on you．

There is a strong chance of short circuits （短路） and fire breakouts during an earthquake． Make sure you turn off electrical connections and gas immediately when an earthquake happens．

During an earthquake， lie beneath an object that is not easily damaged． Do not go near objects that could directly fall on you． Never use the elevator to go down． Stay inside until the shaking stops and it is safe to go outside． Research has shown that most injuries happen when people inside buildings try to go out． Use the staircases at all times．

If you are outdoors， do not take shelter under a tree， streetlights， electric poles or tall buildings． If you are driving， stop your car and stay in a safe place． Do not park your car under a tree or any tall object．

If trapped in debris （瓦砾堆）， cover your mouth with a handkerchief or clothing． Tap on a pipe or wall so rescuers can find you． Use a whistle （哨子） if one is available． Never shout for help． Shouting can cause you to breathe in dangerous amounts of dust． Do not light a match because you may burn yourself． Do not move about or kick up dust．

New research helps to explain why screaming is disturbing and useful.

Screams, like those we hear in horror movies, have a special quality that separates them from other noises we make and hear. These screams are recognized by people all over the world.

【小题1】"Every kid in every culture screams. Every adult in the context of a true fear responds with screams. So it's just a feature of the human mind and brain．”

David Poeppel is a neuroscientist at New York University. He wondered why screams were recognized the same way by people all around the world. So, he and his colleagues set up an experiment.

They recorded screams from movies and from volunteers who took part in the research.【小题2】 Instead, they measured how quickly the sounds in the scream changed in volume. It was in this area-the change in volume that screams stand apart from other sounds.

When the volume of a sound changes that quickly it has a quality called roughness. "【小题3】 David Poeppel and his team found that car alarms, sirens, and alarm clocks also have this quality, this roughness.”

The scientists then studied how this "roughness" changed brain activity. They asked the volunteers to listen to different types of screams and alarms in an MRI scanner, The researchers found that the greater "roughness" of a sound. the more it activates the amygdala.

【小题4】“The amygdala acts like a gauge that says ‘wow, this sound has a lot of roughness in it; that’s particularly alarming and scary. ’"

Screams, it turns out, are a direct link to the part of our brain that tells us whether we should be afraid or not. 【小题5】

Now, we know why a scream.. gets so much attention, So quickly.