1 . Hundreds of native North American plants, often dismissed as weeds, deserve a lot more respect, according to a new study. These plants, distant cousins of foods like cranberries and pumpkins, actually represent a botanical treasure now facing increased threat from climate change, habitat loss and invasive species.

The crops that the human race now depends on, including grains like wheat and tree fruit like peaches, originally were selected or bred(培育) from plants that grew wild hundreds or thousands of years ago. And those ancestral plants like the small wild sunflowers that can be found across the United States, still exist. “If you see them growing along roadsides, those are the ancestors,” says Colin Khoury, a research scientist at the International Center for Tropical Agriculture. Khoury says wild lettuce(莴苣) plants grow along roads, or in backyards, but go unrecognized. “They look nothing like lettuce,” he says. “They are scratchy, thorny, little and ugly.”

Khoury loves these wild relatives of food crops, not just for emotional reasons. “These wild plants are of great value,” he says. That wild sunflower, for instance, can survive in a salty environment that would kill most plants. So plant breeders cross-pollinate(使异花传粉) it with commercial sunflowers and create new varieties that can grow in places where the soil contains more salt. Other wild relatives may be hiding similarly remarkable gifts, Khoury says, such as genes that could help their domesticated(家养的) relatives survive diseases, deal with pests, or adapt to disruptions in the climate.

Khoury and some of his colleagues just finished a survey of about 600 wild crop relatives that grow in North America, and published it this week in the Proceedings of the National Academy of Sciences. They found that the survival chances for most of these plants are being undermined because of things like fires, farming and commercial development. The scientists argue that these endangered species deserve more protection. “It’s more just being aware that these plants actually exist,” Khoury says. “They need protection.”

1. What is the characteristic of wild lettuce plants?

A．They can be commonly seen.	B．They look the same as lettuce.
C．They are selected from grains.	D．They are smooth and beautiful.

2. Why does Colin Khoury consider wild relatives of food crops valuable?

A．They can improve soil quality.

B．They can slow down climate change.

C．They can kill most dangerous wild plants.

D．They can help with domesticated plants’ growth.

3. Which of the following best explains the underlined word in the last paragraph?

A．Assessed.	B．Destroyed.
C．Obtained.	D．Offered.

4. What is the best title for the text?

A．The Distant Cousins of Food Crops Are What We Really Need

B．Scientists Have Found a New Way to Increase Our Food Crops

C．Wild Relatives of Food Crops Deserve Respect and Protection

D．Everyone Should Take Action to Protect Botanical Treasures

2 . 阅读下面短文,在空白处填入1个适当的单词或括号内单词的正确形式。

Rick Howells is the arborist (树木栽培家) for the Shade Tree Commission in Allentown, Pennsylvania. He manages the care of all of the trees in the city,     1    (include) the trees that line the streets.

Trees can make a city prettier, sure. But that’s not    2    (they) only advantage, Howells explained. Trees can save lives by absorbing (吸收)    3    (pollute) from cars and   factories. Trees can also help slow climate change by absorbing carbon dioxide, one of the main    4    (cause) of climate change. In cities, trees provide a home    5    birds and bees. They also offer a calming effect on the community. That is one reason why there    6    (be) less crime in tree-lined areas.

“Trees must be trimmed (修剪) and, if they are diseased, cut down so that they don’t become a risk to the community. It isn’t     7    easy task,” Howells said. “You have to know types of knots (结) for the ropes and    8    (difference) kinds of rigging (索具).” Rigging equipment is tied to trees so that they can be trimmed and cut    9    (safe).

To Howells, taking care of trees isn’t just a job. It’s also a hobby. He loves trees and    10     they bring to a community. “If you take good care of a tree,” he said, “everything around it becomes beautiful, too.”