Do you know that there's a new frontier in 3D printing that's beginning to come into focus: food. Recent development has made possible machines that print, cook, and serve foods on a mass scale. {#blank#}1{#/blank#}

    Food production

    With a 3D printer, a cook can print complicated chocolate sculptures and beautiful pieces for decoration on a wedding cake. {#blank#}2{#/blank#} —it takes years of experience, but a printer makes it easy. A restaurant in Spain uses a Foodini to "re-create forms and pieces" of food that are "exactly the same," freeing cooks to complete other tasks. In another restaurant, all of the dishes and desserts it serves are 3D-printed, rather than farm to table.

    Sustainability

    According to a new study, the global population is expected to grow to 9.6 billion by 2050, and some analysts estimate that food production will need to be raised by 50 percent to maintain current levels. {#blank#}3{#/blank#} 3D food printing could probably contribute to the solution. 3D printing can reduce fuel use and emissions. Grocery stores of the future might stock "food" that lasts years on end, freeing up shelf space and reducing transportation and storage requirements.

Nutrition

    {#blank#}4{#/blank#} Hod Lipson, a professor at Columbia University, said, "Food printing could allow consumers to print food with customized nutritional content, like vitamins. So instead of eating a piece of yesterday's bread from the supermarket, you'd eat something baked just for you on demand."

    {#blank#}5{#/blank#}

    Despite recent advancements in 3D food printing, the industry has many difficulties to overcome. Currently, most ingredients must be changed to a paste(糊状物) before a printer can use them, and the printing process is quite time-consuming, because ingredients interact with each other in very complex ways. On top of that, most of the 3D food printers now are restricted to dry ingredients, because meat and milk products may easily go bad.

A. Challenges

B. Opportunities

C. And the industry isn't stopping there.

D. Sustainability is becoming a necessity.

E. Future 3D food printers could make processed food healthier.

F. Here are some new ways to produce 3D printing.

G. Not everybody can do that.

    Every animal sleeps, but the reason for this has remained foggy. When lab rats are not allowed to sleep, they die within a month. {#blank#}1{#/blank#}

    One idea is that sleep helps us strengthen new memories. {#blank#}2{#/blank#}We know that, while awake, fresh memories are recorded by reinforcing (加强) connections between brain cells, but the memory processes that take place while we sleep have been unclear.

    Support is growing for a theory that sleep evolved（进化） so that connections between neurons (神经元) in the brain can be weakened overnight, making room for fresh memories to form the next day. {#blank#}3{#/blank#}

Now we have the most direct evidence yet that he is right. {#blank#}4{#/blank#}The synapses （神经突触）in the mice taken at the end of a period of sleep were 18 percent smaller than those taken before sleep, showing that the connections between neurons weaken while sleeping .

If Tononi's theory is right, it would explain why, when we miss a night's sleep, we find it harder the next day to concentrate and learn new information--our brains may have smaller room for new experiences.

    Their research also suggests how we may build lasting memories over time even though the synapses become thinner. The team discovered that some synapses seem to be protected and stayed the same size. {#blank#}5{#/blank#} “You keep what matters,”Tononi says.

A. We should also try to sleep well the night before.

B. It's as if the brain is preserving(保存) its most important memories.

C. Similarly, when people go for a few days without sleeping, they get sick.

D. The processes take place to stop our brains becoming loaded(装载) with memories.

E. That's why students do better in tests if they get a chance to sleep after learning.

F. “Sleep is the price we pay for learning,” says Giulio Tononi, who developed the idea.

G. Tononi's team measured the size of these connections, or synapses, in the brains of 12 mice.

Easy ways to keep your brain sharp

    Everyone is forgetful, but as we age, we start to feel like our brains are slowing down a bit — and that can be a very annoying thing. {#blank#}1{#/blank#} Read on for some techniques worth trying.

    ⒈{#blank#}2{#/blank#} 

    People who regularly made plans and looked forward to upcoming events had a 50 percent reduced chance of Alzheimer's disease (早老性痴呆症), according to a recent study. {#blank#}3{#/blank#}Something as simple as setting a goal to have a weekly coffee date with a friend will do. There's evidence that people who have a purpose in life or who are working on long or short-term goals appear to do better. In other words, keep your brains looking forward.

    ⒉Go for a walk.

    Mildly raised glucose (葡萄糖) levels can harm the area of the brain that helps you form memories and physical activity can help get blood glucose down to normal levels. In fact, exercise produces chemicals that are good for your brain. {#blank#}4{#/blank#}

    ⒊Learn something new.

    Take a Spanish class online, join a drawing club, or learn to play cards. A study found that mental stimulation (刺激) limits the weakening effects of aging on memory and the mind. But the best thing for your brain is when you learn something new and are physically active at the same time.{#blank#}5{#/blank#} Or go dancing with your friends.

A. Focus on the future.

B. This can be especially harmful to the aged.

C. It should be something like learning gardening.

D. So take a few minutes each day to do some reading.

E. But don't worry if your schedule isn't filled with life-changing events.

F. Luckily, research shows there is a lot you can do to avoid those moments.

G. In other words, when you take care of your body, you take care of your brain.

    Self-esteem means feeling good about yourself. You can do things to feel better about yourself. Here are some tips to raise your self-esteem.

    Be with people who treat you well. Some people act in ways that tear you down. Others lift you up by what they say and do. Learn to tell the difference. Choose friends who help you feel OK about yourself. Find people you can be yourself with. {#blank#}1{#/blank#}.

    Accept what's not perfect. It's always good to do the best you can. {#blank#}2{#/blank#}, you can't feel good about anything less. Accept your best. Let yourself feel good about that. Ask for help if you can't get past a need to be perfect.

    Focus on what goes well. Are you so used to talking about problems that they've all you see? It's easy to get caught up in what's wrong.{#blank#}3{#/blank#}, it just makes you feel bad. Next time, catch yourself when you complain about yourself or your day. Find something that goes well instead.

    Give and help. {#blank#}4{#/blank#} . Tutor a classmate, help clean up your neighborhood, or walk for a good cause. Help out at home or at school. Make it a habit to be kind and fair. Do things that make you proud of the kind of person you are. When you do things that make a difference your self-esteem will grow.

    Set goals and work toward them. If you want to feel good about yourself, do things that are good for you. Maybe you want to eat a healthier diet, get more fit, or study better.

    {#blank#}5{#/blank#}. Then make a plan for how to do it. Stick with your plan. Track your progress.

A. Make a goal

B. Say helpful things to yourself

C. Be that type of friend for others

D. But when you think you need to be perfect

E. But unless you balance it with what's good

F. When you focus on what's good about yourself

G. Giving is one of the best ways to build self-esteem

    There are some children who love to fly and then there are the kids who are afraid of the unknown. The following tips may help you if you want to travel with your children by plane.

    ●{#blank#}1{#/blank#} If you tell the child he will soon be flying on an airplane and leave it at that, his imagination can turn to fear. Instead, tell him how wonderful it is to fly.

    ●Don't tell children about the dangers of flying. {#blank#}2{#/blank#} And you can promise him that the plane will not crash.

    ●Read a book to your children. {#blank#}3{#/blank#} Reading may also make your children fall asleep.

    ●Bring a comfort thing that your child enjoys. {#blank#}4{#/blank#} Be sure to bring that blanket along as it will provide a safety net for the child. Having this blanket along may also help him fall asleep. Bring a safe electronic device that shows movies or supports video games, and offers children puzzles.

    ●Bring snacks. Children are picky eaters and may not like the food being offered. Three to five hours can be a long time on an airplane without food. {#blank#}5{#/blank#} When they are upset, it is easier to let fear of the unknown take control.

A: Excuse me, Madam. You can't park in front of the shop.

B: I'm so sorry. It's my first time to drive alone. {#blank#}1{#/blank#}

A: {#blank#}2{#/blank#} I think you can park there.

B: {#blank#}3{#/blank#}

A: About two kilometers.

B: Thanks. Can you tell me the way there?

A: You can use the guide map in your car. {#blank#}4{#/blank#}

B: But I don't know how to use it! Can you help me?

A: {#blank#}5{#/blank#} All right, it's OK now.

B: It's very kind of you. Thank you so much!

A: You are welcome.