完形填空,阅读下面的短文，从短文后各题所给的选项中选出能填入空白处的最佳答案。

Bees live in a house that is called a hive. There are three kinds of bees: workers, drones (雄蜂) 1queens. Only one queen bee can live in each hive. If she is lost or dead, the other bees 2 their work.

Workers are very clever and busy. They all join together3 small rooms called cells of wax for their honey. Each worker bee does its own work. Some go out and collect honey from the flowers; 4 stay at home and work inside the hive. The cells5have six sides are made by worker bees. Did you ever look into a glass hive and see them while at work? It is 6to see how busy they always are. Before winter comes, all the drones are driven from the hive7 they don't eat the honey they did not collect.

It is not safe 8 children to be too close to bees. Bees have painful stings they use in their defense (防御).

​

    You may be surprised to learn how many animals actually have a memory. 1 your goldfish can show evidence (证据) of learning ability. If you have a pet fish, try this 2. Every day when you feed the fish, sprinkle (撒) the food only in the same location.

    Keep a record of daily observations (观察) of the fish, taking down notes about the fish's swimming directions or behavior whenever you come to feed it. Before long, the fish should swim to the spot where you sprinkle the food whenever you approach (靠近) the tank. See how it reacts (反应) to your approaching the tank and take notes before, 3, and after your experiment.

In this example of animals' memory, we don't really know if your fish knows the fact that you are going to feed it. But it has showed its 4 ability to learn and to remember.

    Bees 5 with each other in a way which shows an intelligent memory. When a bee finds a good location for gathering nectar (花蜜), it will remember 6 to get to this location from its hive (蜂巢). The bee then returns to the hive and passes along its memory by doing a complex dance to inform the others of where the food was found. It uses wings, legs, antennae (触角) and body to deliver the message. When the dance is over, other bees fly to this location to bring back food for the hive.

    Life in the year 3044 is very different 1  life in the 21st century. We still do many of the things you do, but we do them 2  For example, we now have e-friends to help us and company us. An e-friend is a machine that looks just 3 a human being. It can walk and talk and can do almost 4 we human beings do. My e- friend is a lot like me and we have 5 fun together. She helps me 6 my homework and we often go swimming. She is programmed to take care of me if anything 7, so I always feel safe when we are together.  She can also send me messages, just like old-fashioned emails, and I can download information from her memory. It's great  8an e-friend--I am never lonely and I always have someone to talk 9.

    I would like to tell you more about life in the year 3044, but I have to send my e-friend to clean up my room. Maybe 10 I will be able to travel back in time and visit you.

    Light travels at a very fast speed. It is about a million times1than the speed of sound. You can get some idea of this2by watching the start of a race. If you stand some distance away from the starter, you can see smoke from his gun before the sound gets to your 3.

    This great speed of light4some strange facts. Sunlight5about 8 minutes to get to us. If you look at the light of the moon tonight, 6 that the light rays(光线)leave the moon 1.3 seconds before they get to you. The nearest star is so7away that the light which you can see from it tonight started to8towards you several years ago. In some cases, the light from one of tonight's stars had started on its journey to you before you were born.

    So, to be exact, we can't say, "The stars are shining 9."We have to say instead, "The stars10pretty. They were shining several years ago, but their light has only just got to the Earth."

Orchids and the environment

    The orchid is a beautiful flower that can grow indoors or outdoors. There are over 25,000 different species of orchids, so it's one of the largest families of p{#blank#}1{#/blank#} in the world. Orchids can come in many different c{#blank#}2{#/blank#}as well, such as white, purple, pink, blue and yellow. There are several conditions that help orchids grow so well. Orchids need the right temperature, as well as the right amount of sunlight, soil, and water in order to l{#blank#}3{#/blank#}.

    F{#blank#}4{#/blank#} indoor orchids, it is much easier to control these conditions. For example, orchids usually need to be watered once a week, and you can control how much water you give to the plant. Also, many orchids grow best if they had indirect sunlight b{#blank#}5{#/blank#} direct sunlight will burn them. Indoor orchids can be placed near windows with curtains or blinds. This will protect them and give them the indirect sunlight they need.

    However, as to orchids that grow outdoors in the wild, global warming can become a threat. Unfortunately, global warming affects temperature, light and rain. All these factors will affect the way orchids live and grow. Most orchids will live c{#blank#}6{#/blank#} within a narrow temperature range of 18.3 to 23.8 degrees Celsius. Global warming can increase temperatures beyond the natural range for these flowers. Unfortunately, this can destroy orchids because they can't survive in hot, dry conditions. Second, air pollution can create acid rain. Acid rain is created when gases from fossil fuels combine with water in the air to form acids. When acid rain falls on plants and trees, it destroys the n{#blank#}7{#/blank#} balance of the soil and kills them.