1 . Common water plant could provide a green energy source. Scientists have figured out how to get large amounts of oil from duckweed, one of nature’s fastest-growing water plants. Transferring such plant oil into biodiesel (生物柴油) for transportation and heating could be a big part of a more sustainable future.

For a new study, researchers genetically engineered duckweed plants to produce seven times more oil per acre than soybeans. John Shanklin, a biochemist says further research could double the engineered duckweed’s oil output in the next few years.

Unlike fossil fuels, which form underground, biofuels can be refreshed faster than they are used. Fuels made from new and used vegetable oils, animal fat and seaweed can have a lower carbon footprint than fossil fuels do, but there has been a recent negative view against them. This is partly because so many crops now go into energy production rather than food; biofuels take up more than 100 million acres of the world’s agricultural land.

Duckweed, common on every continent but Antarctica, is among the world’s most productive plants, and the researchers suggest it could be a game-changing renewable energy source for three key reasons. First, it grows readily in water, so it wouldn’t compete with food crops for agricultural land. Second, duckweed can grow fast in agricultural pollution released into the water. Third, Shanklin and his team found a way to avoid a major biotechnological barrier: For the new study, Shanklin says, the researchers added an oil-producing gene, “turning it on like a light switch”by introducing a particular molecule (分子) only when the plant had finished growing. Shanklin says, “If it replicates (复制) in other species-and there’s no reason to think that it would not — this can solve one of our biggest issues, which is how we can make more oil in more plants without negatively affecting growth.”

To expand production to industrial levels, scientists will need to design and produce large-scale bases for growing engineered plants and obtaining oil — a challenge, Shanklin says, because duckweed is a non-mainstream crop without much existing infrastructure (基础设施).

1. What can people get from duckweed firsthand?

A．Plant oil.	B．Stable biodiesel.
C．Sustainable water.	D．Natural heat.

2. What does paragraph 4 mainly convey?

A．Options for renewable energy.

B．Reasons for engineering genes.

C．The potential of revolutionary energy source.

D．The approach to avoiding agricultural pollution.

3. What is the decisive factor to mass-produce the plant?

A．Industrial levels.	B．Unique design.
C．Academic research.	D．Basic facilities.

4. What would be the best title for the text?

A．Duckweed Power	B．Duckweed Production
C．Genetic Engineering	D．Genetic Testing

2 . You’ll only find cherry blossoms in a handful of countries.

Called sakura in Japan, the cherry blossoms of Yoshino and Kyoto are world-famous. Tourists flock to the country each spring to try their hand at a centuries-old activity “flower viewing”. You don’t have to fly to Japan to see them, though. In the US, the cherry blossoms of Washington, D.C., New York City, Philadelphia, St. Louis, Seattle, San Francisco, and Boston are all beautiful in their own way. The flowers can also be viewed in many European and Asian countries, as well as Brazil and Australia in the southern hemisphere.

There are hundreds of cherry tree varieties.

Japan in particular is home to hundreds of types of cherry trees -possibly more than 600.Some types bear fruit, while others don’t. The flowers of many trees change from dark pink to light pink to white throughout the different stages of blossoming, while others progress from greenish yellow to white to pink. One variety, called Kanzan, was bred to have “double blossoms” — or up to28 petals (花瓣) on each flower, compared to the Yoshino tree’s five petals.

You can get arrested for picking a cherry blossom in Washington, D. C.

Resist the urge to take a cherry blossom home with you as a souvenir. In D.C. at least, breaking off a blossom or branch is viewed as destruction of federal property. Those who break this rule could receive a citation (传票), or worse, be arrested. It goes without saying that it’s also illegal to climb the trees. If they sustain damage to their branches, they will never be able to grow new blossom on that particular branch again.

Both the blossoms and leaves are edible.

In Japan, no part of the cherry blossom tree pes to waste. The preserved leaves are used as edible mochi wrappers (a rice cake filled with sweet bean paste), and a number of seasonal snacks feature sakura as a key ingredient Sakura-flavored versions of Pepsi, Coke, tea, and even Starbucks lattes are all popular drinks. You can also find Kit Kats and Pocky snack sticks that taste like sakura.

They were the inspiration behind a record-setting LEGO sculpture.

Legoland Japan, a theme park in Nagoya, set a Guinness World Record in 2018 for the largest LEGO brick cherry blossom tree ever made. The trees stood 14 feet tall, weighed over 7000 pounds, and consisted of more than 800,000 LEGO bricks.

1. In which country can’t you see cherry blossoms according to the passage?

A．America.

B．China.

C．Germany.

D．Egypt

2. What can be learned from the passage?

A．Climbing cherry trees is tolerable in Washington.	B．Sakura-flavored snacks and drinks are welcomed.
C．Kanzan sakura is better than Yoshino sakura.	D．The largest cherry blossom tree grows in Japan.

3. Who is the article meant for?

A．A passionate environmentalist.	B．An ecological researcher.
C．A student interested in plants.	D．A tourist in Japan