When you're not at home, many worries may start to crowd your mind. Did I turn the coffee maker off? Did I lock the door? Are the kids doing their homework or watching television? With a smart home, you can quiet all of these worries.

　　　A smart home is a home with a communication network. This network connects devices(装置),such as lights and TV sets, and allows them to be controlled from far away through electrical wiring, mobile phone communication or WiFi over the internet.

　　　More and more people may start to consider owning a smart home, because it makes life much more convenient. It can help keep your room at a certain temperature. It can record what happens inside the home and send the video to your phone. When you are on vacation abroad, you can use a smart home controller to switch on or off the electricity when necessary. Some smart homes can receive a visitor, allowing him to come in and offering him a drink. They can even feed the cat and water the plants.

　　　Besides, smart homes are easy to fix. Most smart home technology and devices are wireless and can be set up with a minimum of tools, using only the guiding information. When a problem appears, you can deal with it yourself without paying a professional.

　　　However, for home-users, the smart home technology is far from perfect. It can be rather expensive to own the technology and the devices. Also, because the smart home system(系统)allow its owner to get home information from anywhere, it leaves the home easy to be attacked by hackers(黑客),who may secretly use or change the information in the system.

　　　Now, many scientists are excited at the future of smart home technology. Imagine being able to get fashion advice from your mirror, or receive food shopping suggestions from your refrigerator. While there are others who worry that those smart devices will make people lazier and lonelier. Whatever it is, one thing is for sure—smart home technology will change the way we live and work.

    Honey(蜂蜜）from African(非洲）forest is very delicious.

    Most people and many animals like eating it. However, the only way for them to get that honey is to find a wild bees' nest(蜂巢）and take honey from it. Often, these nests are high up in trees, and it is difficult to find them. But in parts of Africa, people and animals have a strange helper — a little bird called a honey helper.

    In fact, the honey helper does not like honey, but it likes the wax(蜂蜡）in the nest. The little bird cannot reach the wax because it is inside the bees' nest. So, when it finds a nest, it looks for someone to help. The little bird sings loudly to get the attention(注意） of both passing animals and people. When it has their attention, it flies through the forest, waiting for the following animal or person that loves honey. Then it helps them find the nest. When they finally arrive at the nest, the follower tries to get the delicious honey and the bird waits and watches. Some of the honey and the wax always fall to the ground, and this is when the bird takes its share.

    Scientists do not know why the bird likes eating the wax, but they seem to be able to smell the wax far away.

    It's important to learn about protecting our environment. Here is a 5R rule for us:

    Reduce

    If you want to reduce waste, you should use things wisely(明智地). A larger number of trees are cut down to make paper. If everyone uses paper carelessly, soon we will not have any trees left. Other things are also being wasted, and people don't know what to do with the waste in big cities. So it is necessary to use things wisely.

    Reuse

    You should always think of reusing the usable things before throwing them away. For example, you can give your clothes you do not wear any more to the poor. In a family, you may pass on such clothes to younger brothers or sisters.

    Recycle

    Bottles, cans and paper can easily be recycled. By recycling them we save lots of time and money. For example, Coke cans are sent to a factory, where they are smashed flat (压平) and melted(融化) and the metal things are made for new Coke cans.

    Recover(恢复)

    When you buy a box of apples, there may be a few rotten(腐烂的) apples, you have two choices(选择): One is to throw the whole apples away, or you can cut off the rotten parts and keep the good parts. In the way, you are recovering the eatable(能吃的) parts of food.

    Repair

    If one of the legs of your table is broken, you can repair it. If you want to change for better ones, it is better for you to sell the old things or give them to other people who can use them after doing some repair.

    Traffic rules help to keep order on the road. They also help to keep people s{#blank#}1{#/blank#}. The pedestrian (行人) has as many rules to f{#blank#}2{#/blank#} as the driver of a car. You should walk on the sidewalk (人行道) or at the side of the road. Always look {#blank#}3{#/blank#} (careful) before you walk across the street.

    If you like riding {#blank#}4{#/blank#} bike, don't ride in the middle of the road or run through red traffic lights. When you ride a bike w{#blank#}5{#/blank#} a friend, don't look around or talk.

    If you drive a car, you should s{#blank#}6{#/blank#} down at the traffic lights. You must always wear a seat belt (安全带), Without belts b{#blank#}7{#/blank#} the driver and the passengers may be badly hurt in a sudden accident.

    You may not need to take a bus, but look out if you have to travel in one. Get on or get off a bus only when it comes to a s{#blank#}8{#/blank#}. When it is full, don't try to get inside, o{#blank#}9{#/blank#} you may fall off.

    Traffic rules are also {#blank#}10{#/blank#} (call) Road Safety rules. The maxim (格言) for all road users is "Thinking about others".

The Netherlands needs thousands of new houses because the country {#blank#}1{#/blank#}(have) a growing population. Anyway, it may not have to build all those houses. Some of {#blank#}2{#/blank#}(they) can be printed.

 {#blank#}3{#/blank#}(recent), the government has been working together with a university and some building companies to build houses that are fully 3D-printed. As volunteers, an old couple has become the first people in Europe to move into such {#blank#}4{#/blank#} house.

With two {#blank#}5{#/blank#}(bedroom) and a big living room, the house was built layer(层) by layer, using a huge 3-D printer and special cement(水泥). After being printed out, the house {#blank#}6{#/blank#} (carry) by a truck to the building site, and a roof(屋顶) and windows were later added. It took around 120 hours {#blank#}7{#/blank#} (finish) this 3D-printed house. Usually, it takes about one or two years to build a house in the {#blank#}8{#/blank#} (tradition) way.

The couple will live {#blank#}9{#/blank#} this house for six months, with a monthly pay of 800 euros (欧元). The cost seems a little bit high, {#blank#}10{#/blank#} they think it is much cheaper than living in a hotel.

Dear Mike,

My name is Li Hua.