1 . With the Covid-19 virus sweeping the globe, the science on quitting smoking offers welcome news for smokers who want to build up their defenses in case they contract the virus. Though it may still take many months for a smoker's lungs to heal from damage caused by long-term smoking, your health can noticeably improve in the days and weeks after quitting in ways that could make a difference against the virus. Covid-19 creates an added sense of urgency, and there's enough reason to believe that quitting smoking during the pandemic（流行病）could increases your opportunities of fighting off the virus.
If you make the decision to quit, the cilia（纤毛）in your lungs are one of the first parts of your body to heal. These hair-like projections wave back and forth like a brush as air moves in and out of your lungs. They help your body fight off colds and infection. They also help clear mucus（黏液）, so if they're not functioning as well as they should, mucus can build up in the lungs. Your body's tendency to cough during an infection helps inspire the bodily process of clearing out mucus. That's vital in fighting the Covid-19 condition. The elderly are at a greater risk for too much lung fluid that often limits breathing following coronavirus infection because they don't have a strong enough cough to clear it up.
A second short-term gain from quitting smoking comes from reducing ongoing inflammation（炎症）in your body, which can make you infect Covid-19 more easily. Having your lungs in as good of shape as you can in case of a corona virus infection is key.
Besides lung-related issues, quitting smoking can also deliver healthy benefits to the heart that could help prevent possible heart attacks, which are another cause of death in Covid-19 cases. After you quit smoking, your blood becomes thinner and less possible to setting. Heart attacks are less likely. One reason this happens is because smoking makes it harder for the heart to distribute blood throughout the body.
1. What is the use of the lung cilia?| A．Cleaning up the lungs. | B．Killing the Covid-19 virus. |
| C．Predicting lung infections. | D．Reducing breathing difficulty. |
| A．They cannot go out during the pandemic. | B．There is too much mucus in their lungs. |
| C．Most of them are heavy smokers for years. | D．They are lacking in the care of their children. |
| A．Strengthen the heart muscle. | B．Turn blood to be much thicker. |
| C．Make the blood flow smoother. | D．Speed the heartbeat up apparently. |
| A．Quitting smoking can help defend the Covid-19. |
| B．Ways to make a difference against corona viruses. |
| C．The Covid-19 virus is threatening humans worldwide. |
| D．Protecting the smokers' lungs to heal from damage. |
2 . As trees across the northern areas turn gold and deep red, you can find autumn colors in parks and woodlands, in the cities, countryside, and mountains. People are wondering what these colors are for. For years, scientists have worked to understand the changes that happen to trees in the autumn. Up to now there have been different explanations for why natural selection makes autumn colors so widespread.
Dr. Hamilton from Oxford University proposed that bright autumn leaves contained a message: they warn insects to leave them alone. In autumn, insects choose trees where they will lay eggs. When the larvae（幼虫）come out the next spring, they feed on the trees, often with a result of destruction of the trees. Dr. Hamilton suggested that trees could ward off these insects with poisons. They could have strong defenses by letting egg-laying insects know what was in store for their eggs.
Dr. Hamilton and students turned the theory into a mathematical model, which showed that warning signals could indeed drive the evolution（进化）of bright leaves. It was a first attempt to see what was out there.
A research team from the University of Wisconsin gave a quite different explanation. “If you are up here in Wisconsin, by the time leaves change, all the insects that feed on leaves are gone.” Dr. Hoch said. He believed that autumn colors served mainly as protection.
According to Dr. Hoch and his team, autumn colors might be able to protect the leaves from sun damage or frost（冰冻）injury—in other words, they actually act as a sunscreen to avoid the destruction to the leaves. Besides, autumn colors might protect the leaves from water loss. If the cells in the leaves become dry, the connections between the cells will be weakened and leaves will break off.
Although there are different explanations about autumn colors, it has really given them a deeper concern for this time of year. “People sometimes say that science makes the world less interesting by just explaining things away,” one famous biologist said. “But with autumn leaves, the more you know about them, the more amazed you are.”
1. According to Dr. Hamilton, there is a connection between________.| A．the size of leaves and the survival of insects |
| B．the size of leaves and the behavior of insects |
| C．the size of leaves and the quality of insects |
| D．the size of leaves and the number of insects |
| A．Climate has an influence on the color of the leaves |
| B．Sun damage and frost injury drive the insects away |
| C．the color of autumn leaves has a protective function |
| D．Autumn colors bring great destruction to the leaves |
| A．catch |
| B．attract |
| C．ignore |
| D．prevent |
| A．The evolution of colorful leaves |
| B．The secret to autumn leaves’ changes |
| C．The charm autumn colors |
| D．The role of leaves’ being protection |
The Hong Kong-Zhuhai-Macao Bridge (HZMB), the
The project involved more than 400 new patents, broke seven world records, and featured
