Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.

Big climate changes in the last million years might have come from something very small: dust from outer space.

   Earth changes between ice ages and warm periods in a(n) __1.__ that includes several cycles, including a __2._ one that lasts 100,000 years. Scientists __3.__suggested this cycle might be due to changes in the inflow of cosmic(????) dust.

   The idea is that Earth _4.__above and below the imaginary plane that runs through the sun and Jupiter(???), completing a cycle every 100,000 years. So maybe it encounters __5._varying amounts of dust during each cycle that produce the climate trend.

   Now there is some __6.__, from ancient cosmic dust recovered in ocean-floor drilling near the Azores islands west of Portugal. The large quantity of the dust rises and falls with a wonderful 100,000 year cycle during the period analyzed, 253,000 years to 458,000 years ago. Periods of more dust are related to__7.__ climates.

   But that is a long way from showing that the dust __8.__ climate. Some scientists argue that it is not clear how cosmic dust would make the climate warmer while dust from volcanoes is known to make it cooler. They say the cosmic dust is so thin that it is hard to see how it could have any climate__9.__.

   Nevertheless, the new study shows scientists have to take the cosmic dust idea seriously.

Anyone for rocket salad?        The Chinese are now growing huge vegetables from seeds they sent into space.

If you’re the type who worries about the air miles traveled by fruits and vegetables,  these beauties aren’t for you. It’s because they have traveled a little further than most.

The seeds from which they grew were fired into space, where they orbited the earth for two weeks. Once they returned they were grown in hothouses, producing the monster kinds seen here.

China, which is behind these space fruits and vegetables, says they could be the answer to the world’s food crisis.

The 21-pound tomatoes, nine-inch chilies, 15-stone pumpkins and large watermelons growing at the Guangdong Academy of Agricultural Sciences’ hothouses can feed many more than their smaller cousins, and may have more nutrients, the scientists say.

Researcher Lo Zhigang said, “Traditional agricultural development has taken us as far as we can go and demand for food from a growing population is endless. Space seeds offer the opportunity to grow fruits and vegetables bigger and faster.”

He admitted he and his colleagues could not explain why time in orbit caused the seeds to change genetic structure. But they guessed exposure to the cosmic(宇宙的) radiation that attacked the spacecraft in orbit, as well as the near zero gravity conditions, microgravity, could play a part.

“We don’t think there’s any threat to human health because the genes themselves do not change; just their order changes,” he said. “With genetically-modified(GM) crops you have seen environmental problems because they have added genes that can damage other organisms. But with space seeds they don’t gain genes; they can only lose them.”

He also claimed the Vitamin C content in some space vegetables was nearly three times higher than in common vegetables, while levels of zinc are also increased.

Western scientists are doubtful. NASA researchers who have experimented with seeds in space say there is not enough benefit to show the cost is reasonable.

72. What do the underlined words “these beauties” in paragraph 2 probably refer to?

         A. Beautiful views along the air routes.           B. Traveling experiences in space.

         C. Seeds fired into space.                                     D. Giant vegetables.

73. We can infer from Lo’s words in paragraph 6 that       .

         A. our conventional agriculture has developed too slowly

         B. we are asking too much from nature

         C. space seeds may help meet our demand for food

         D. we’ll grow crops in space in the future

74. Why the seeds changed their genetic structure      .

         A. remains to be proved                                      

    B. is discovered by Lo Zhigang

         C. has something to do with die conditions in hothouses

         D. is due to the radiation that attacked them directly

75. Comparing Gm crops and space crops, we can see that      .

         A. space crops grow faster                                 

    B. space crops are more environmentally friendly

         C. GM crops are less a threat to human health  

    D. GM crops have fewer nutrients

Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.

Big climate changes in the last million years might have come from something very small: dust from outer space.

   Earth changes between ice ages and warm periods in a(n) ____ that includes several cycles, including a ___ one that lasts 100,000 years. Scientists ____suggested this cycle might be due to changes in the inflow of cosmic(宇宙) dust.

   The idea is that Earth ___above and below the imaginary plane that runs through the sun and Jupiter(木星), completing a cycle every 100,000 years. So maybe it encounters ___varying amounts of dust during each cycle that produce the climate trend.

   Now there is some ____, from ancient cosmic dust recovered in ocean-floor drilling near the Azores islands west of Portugal. The large quantity of the dust rises and falls with a wonderful 100,000 year cycle during the period analyzed, 253,000 years to 458,000 years ago. Periods of more dust are related to____ climates.

   But that is a long way from showing that the dust ____ climate. Some scientists argue that it is not clear how cosmic dust would make the climate warmer while dust from volcanoes is known to make it cooler. They say the cosmic dust is so thin that it is hard to see how it could have any climate____.

   Nevertheless, the new study shows scientists have to take the cosmic dust idea seriously.

D
Anyone for rocket salad? The Chinese are now growing huge vegetables from seeds they sent into space.
If you are the type who worries about the air miles travelled by fruits and vegetables, these beauties aren’t for you. It's because they have travelled a little further than most.
The seeds from which they grew were fired into space, where they orbited the earth for two weeks. Once they returned they were grown in hothouses, producing the monster kinds seen here.
China, which is behind these space fruits and vegetables, says they could be the answer to the world's food crisis.
The 21-pound tomatoes, nine-inch chillies, 15-stone pumpkins and large watermelons growing at the Guangdong Academy of Agricultural Sciences’ hothouses can feed many more than their smaller cousins, and may have more nutrients, the scientists say.
Researcher Lo Zhigang said, "Traditional agricultural development has taken us as far as we can go and demand for food from a growing population is endless. Space seeds offer the opportunity to grow fruits and vegetables bigger and faster. "
He admitted he and his colleagues could not explain why time in orbit caused the seeds to change genetic structure. But they guessed exposure to the cosmic（宇宙的）radiation that attacked the spacecraft in orbit, as well as the near zero gravity conditions, microgravity, could play a part.
"We don't think there's any threat to human health because the genes themselves do not change; just their order changes," he said. "With genetically-modified（GM）crops you have seen environmental problems because they have added genes that can damage other organisms. But with space seeds they don't gain genes; they can only lose them. "
He also claimed the Vitamin C content in some space vegetables was nearly three times higher than in common vegetables, while levels of zinc are also increased.
Western scientists are doubtful. NASA researchers who have experimented with seeds in space say there is not enough benefit to show the cost is reasonable.
63. What do the underlined words "these beauties" in Paragraph 2 probably refer to ______?
A. Beautiful views along the air routes.          B. Travelling experiences in space.
C. Seeds fired into space.                     D. Giant vegetables.
64. We can infer from Lo’s words in Paragraph 6 that _______.
A. our conventional agriculture has developed too slowly.
B. we are asking too much from nature
C. space seeds may help meet our demand for food
D. we'll grow crops in space in the future
65. Why the seeds changed their genetic structure _______.
A. remains to be proved
B. is discovered by Lo Zhigang
C. has something to do with the conditions in hothouses
D. is due to the radiation that attacked them directly
66. What can be inferred from the last paragraph?
A. Western scientists’ doubt is unreasonable.
B. Western scientists don’t believe that Chinese scientists have succeeded in the experiment.
C. Western scientists have proved space seeds to be of no benefit.
D. Western scientists think the cost of space seeds outweighs the benefits

Anyone for rocket salad? The Chinese are now growing huge vegetables from seeds they sent into space.

If you are the type who worries about the air miles travelled by fruits and vegetables, these beauties aren’t for you. It's because they have travelled a little further than most.

The seeds from which they grew were fired into space, where they orbited the earth for two weeks. Once they returned they were grown in hothouses, producing the monster kinds seen here.

China, which is behind these space fruits and vegetables, says they could be the answer to the world's food crisis.

The 21-pound tomatoes, nine-inch chillies, 15-stone pumpkins and large watermelons growing at the Guangdong Academy of Agricultural Sciences’ hothouses can feed many more than their smaller cousins, and may have more nutrients, the scientists say.

Researcher Lo Zhigang said, "Traditional agricultural development has taken us as far as we can go and demand for food from a growing population is endless. Space seeds offer the opportunity to grow fruits and vegetables bigger and faster. "

He admitted he and his colleagues could not explain why time in orbit caused the seeds to change genetic structure. But they guessed exposure to the cosmic（宇宙的）radiation that attacked the spacecraft in orbit, as well as the near zero gravity conditions, microgravity, could play apart.

"We don't think there's any threat to human health because the genes themselves do not change; just their order changes," he said. "With genetically-modified（GM）crops you have seen environmental problems because they have added genes that can damage other organisms. But with space seeds they don't gain genes; they can only lose them. "

He also claimed the Vitamin C content in some space vegetables was nearly three times higher than in common vegetables, while levels of zinc are also increased.

Western scientists are doubtful. NASA researchers who have experimented with seeds in space say there is not enough benefit to show the cost is reasonable.

56. What do the underlined words "these beauties" in Paragraph 2 probably refer to ______?

A. Beautiful views along the air routes.

B. Travelling experiences in space.

C. Seeds fired into space.

D. Giant vegetables.

57. We can infer from Lo’s words in Paragraph 6 that _______.

A. our conventional agriculture has developed too slowly.

B. we are asking too much from nature

C. space seeds may help meet our demand for food

D. we'll grow crops in space in the future

58. Why the seeds changed their genetic structure _______.

A. remains to be proved

B. is discovered by Lo Zhigang

C. has something to do with the conditions in hothouses

D. is due to the radiation that attacked them directly

59. What can be inferred from the last paragraph?

A. Western scientists’ doubt is unreasonable.

B. Westem scientists don’t believe that Chinese scientists have succeeded in the experiment.

C. Western scientists have proved space seeds to be of no benefit.

D. Western scientists think the cost of space seeds outweighs the benefits.