1 . “Flying insects don’t fly directly to lights from far away because they’re attracted to them, but appear to change course toward a light if they happen to be passing by due to a strange inborn biological response,” writes Samuel Fabian, a bioengineer, in a research paper.
Until now, the leading scientific hypothesis has been that insects use the moon’s light to direct the way at night and mistake artificial lights for the moon. But this idea doesn’t explain why insects that only fly during the day also gather around lights.
To find out what really happens, Samuel’s team track the precise movements of insects in the wild around lights using a high-speed camera. This revealed two notable behaviours. First, when insects fly above lights, they often invert (转向) themselves and try to fly upside down, causing them to fall very fast. Just after insects pass under a light, they start doing a ring road. As their climb angle becomes too steep, they suddenly stop and start to fall. Second, when insects approach a light from the side, they may circle or “orbit” the light.
The videos show that the inversions sometimes result in insects falling on lights. It can appear to the naked eye as though they are flying at the lights. “Instead, insects turn their dorsum toward the light, generating flight perpendicular(垂直) to the source,” the team write. It is common to the two behaviours that the insects are keeping their backs to the light, known as the dorsal light response (DLR). This DLR is a shortcut for insects to work out which way is up and keep their bodies upright, as the moon or sun is usually more or less directly above them, and this direction allows them to maintain proper flight attitude and control. They also find that the insects fly at right angles to a light source, leading to orbiting and unstable flights as the light’s location relative to them changes as they move.
Samuel’s team suggest that a possible outcome of the research could help the construction industry to avoid the types of light that most attract insects.
1. What does the research focus on?A.Why insects gather around lights. |
B.Where artificial lights lead insects to. |
C.What biological response insects are born with. |
D.How to design environment friendly artificial lights. |
A.They fly directly to lights. | B.They circle close to lights. |
C.Their flying speed is steady. | D.Their inversions can be controlled. |
A.balance their flying | B.keep their route straight |
C.decide their body positon | D.shorten their flight distance |
2 . 阅读下面短文,根据短文内容填空。在未给提示词的空白处仅填写1个适当的单词,在给出 提示词的空白处用括号内所给词的正确形式填空。
A new study shows rapid decline in insect populations. A growing number of the Earth’s insect population now can
Pandas
4 . Amid rolling farms and green pasture 150 miles northwest of Sao Paulo, Brazil, two tropical forests bloom as one. The first consists of a single species, row after row of non-native eucalyptus (桉树), planted in perfect lines like carrots. The other is haphazard, an assortment of dozens of varieties of native saplings.
There’s no denying it: This forest looks ridiculous. The gangly (修长的) eucalyptuses shoot like witch fingers high above patches of stubby fig (矮壮的无花果树) and evergreen trees. Yet these jumbled 2.5-acre stands of native trees, ringed by fast-growing exotics, are among many promising efforts to resurrect the planet’s forests.
The eucalyptuses, says Pedro Brancalion, the University of Sao Paulo agronomist who designed this experiment, get big so quickly they can be cut after five years and sold to make paper or fence posts. That covers nearly half or more of the cost of planting the slow-growing native trees, which then naturally reseed ground that has been laid bare by the harvest. And this process doesn’t hamper natural regeneration.
You needn’t look far these days to find organizations trying to save the world by growing trees. Too often, tree-planting groups are so focused on getting credit for each seedling planted that they ignore what matters most: What kind of woodland is created? At what cost? And most importantly: How long will it last? Using the numbers of trees planted as a magic “proxy for everything,” Brancalion says, you “spend more money and get lower levels of benefits.” You can literally miss the forest for the trees.
Tree planting seems like a simple, natural way to counter the overwhelming crises of climate change and biodiversity loss. Trees provide wildlife habitats and slurp carbon dioxide from the atmosphere. No wonder trees are hailed as the ideal weapon. Yet for every high-profile planting operation, devastating failures have occurred. In Turkey, Sri Lanka, and Mexico, mass plantings have resulted in millions of dead seedlings or have driven farmers to clear more intact forest elsewhere. Trees that have been planted in the wrong places have reduced water yields for farmers, destroyed highly diverse carbon-sucking grassland soils, and allowed for invasive vegetation to spread. Simply reforesting the planet isn’t going to do much if we don’t also start cutting down on our emissions from the burning of coal, oil, and natural gas. Tree planting also can’t replace old-growth forests. Saving them is even more important than growing new forests.
So, what should we do?
To Brancalion, the answer is obvious: Restore native forests, mostly in the tropics, where trees grow fast and land is cheap. While that may require planting, it may also call for the clearing out of invasive grasses, the rejuvenation (使有活力) of soils, and crop yield improvements so that farmers will need less land for agriculture and more can be allowed to revert back to forests.
The combining of eucalyptus harvests with native plantings is just one more reminder that successful restoration must provide value to local communities. In many cases, if we let nature do the heavy lifting, Brancalion says, “the forest can regrow quite effectively.”
1. What can we learn from the first three paragraphs?A.The non-native eucalyptuses bring profits that can pay for planting native saplings. |
B.The non-native eucalyptuses compete with native saplings for water, nutrients, and light. |
C.The variety of trees being planted determines whether or not the restoration will succeed. |
D.Planting fast-growing exotics together with local trees does harm to the natural environment. |
A.emphasize the significance of protecting existing forests |
B.explain why tree planting is regarded as the ideal solution |
C.illustrate the serious problems planting campaigns can cause |
D.indicate the most important point tree-planting groups ignore |
A.clear more forest to improve crop yields for farmers |
B.combine harvests of fast-growing exotics with native plantings |
C.restore native forests in the tropics and clear out invasive grasses |
D.take into consideration the benefits of reforestation to local communities |
A.Plant trees—and time will tell. | B.Plant trees—but don’t overdo it. |
C.Plant trees—and save the world. | D.Plant trees—but mind the variety. |
1. What are the highest temperatures in Northern India now?
A.About 35℃. | B.Almost 40℃. | C.Over 45℃. |
A.About 200. | B.About 1,000. | C.About 2,000. |
A.Government projects will be done at night. |
B.Bottles of water will be sold at low prices. |
C.School days will be reduced. |
A.Cooler. | B.All the same. | C.Hotter. |
A Weather Report in Australia
New South Wales | There is a warning in place as |
Queensland | At least |
Northern Territory | Residents should only experience light showers, and it will remain |
Perth | There will be |
Geraldton | Rain showers will come in from the |
For a herder (放牧人) in Africa, the hardest part of the job is searching for cattle
Smog hits Beijing frequently,
1. 交流的原因;
2. 建议交流的具体内容;
3. 交流时间和其他相关事项。
注意:词数不少于60。
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Several mass extinction events have occurred in the course of our planet’s history. Scientists say that previously the