题目内容
Farmers may not be able to prevent natural disasters, but they can at least try their best to reduce losses.
For example, they can plant crops that are more likely to survive extreme weather. In north-central Vietnam, people with small farms do not plant rice between September and December. Seasonal rains might destroy the rice. So instead, they plant lotus seeds on raised beds. The United Nations Food and Agriculture Organization says the lotus seeds bring a good price in local markets.
Farmers in the Philippines are showing new interest in crops like winged beans, string beans, arrowroot and cassava. The Asian Disaster Preparedness Center says traditional crops like these can survive the fierce storms that often strike the islands.
The United Nations says some African farmers grow bambara groundnuts during long dry periods. The seeds of this drought-resistant plant can be boiled for eating or for making flour.
In some parts of the world, farmers grow vetiver grass. Researchers in Thailand wrote about vetiver in 2007 in the journal Science Asia. They noted that the grass can absorb and control the spread of harmful waste waters, like those from pig farms.
Agricultural expert and author William Rivera says vetiver resists difficult conditions. It reduces damage from heavy rains. And vetiver planted on earthen dams may strengthen them against breaks and flooding.
William Rivera also speaks approvingly of alfalfa. Its deep roots can find and take up groundwater. Those roots also help hold the soil against winds. And alfalfa can be a valuable food source for animals.
The deep and extensive roots of sunflowers make them another good candidate for resisting extreme conditions. The tall plants have brightly colored heads that provide seeds and oil.
North Dakota grows more hectares of sunflowers than any other American state. But North Dakota is better known as a top wheat producing state.
Hans Kandel works at the North Dakota State University Extension Service in Fargo. He says farmers in some parts of North Dakota plant wheat that is ready to harvest in only about one hundred days. That way it can grow before the hot, dry months of July through September.
67.The underlined part “bring a good price in local markets” in the 2nd paragraph implies that lotus seeds _______.
A. can bring the local farmers more profit
B. will satisfy the needs of the local people
C. are what the local farmers eat every day
D. don’t sell very well because of their high prices
68.Vetiver grass is planted because it can _______.
A. be a valuable food source for animals B. survive the fierce storms in summer
C. provide seeds and oil D. be useful in many aspects
69.From the last paragraph we can see that the farmers in North Dakota _______.
A. are not hardworking so they are suffering from poverty
B. are good at taking advantage of the weather conditions
C. don’t have enough knowledge of weather and farming
D. plant more sunflowers than wheat
70.From this passage we may safely conclude that _______.
A. weather conditions are always decisive factors in agriculture
B. some crops can help farmers to fight against extreme weather
C. the species of the world are changing quickly
D. agriculture is developing fast in the world
67---70 ADBB
解析
In some countries in which there is very little rain at any time, the farmers have to irrigate their fields. Irrigation is easy enough if there is a great river near the crops, and if there is plenty of water in it. Canals carry the river water to the fields when necessary. In some seasons there may be too much water in the river, and the water may flood all the land near it. At other times the river water may not be enough for all the farmers, and then it will be difficult to irrigate the fields.
To prevent these difficulties, a dam may be built across the river. This will store water for dry seasons, and in wet seasons it will prevent the flooding of the land. A great lake will, no doubt, be formed behind the dam, and this may mean that houses and fields will be covered with water. Most people will accept that and will be ready to move to other places. Then the country can have the right amount of water at all times; more crops will be grown, there will be more food for everyone, and there will be no more floods.
Dams have been built for centuries in different parts of the world. Modern dame are usually built of concrete(混凝土)but earth dams were used in India and Sri Lanka about 2500 years ago. There was another across the River Tigris very long ago, and large numbers of irrigation canals were made in Iraq to irrigate the land. The Romans were great dam-builders and there was also a famous dam at Ma’ rubin Arabia.
We cannot use sea water for irrigation; the salt will not allow the crops to grow. Fresh water is always needed, and it is very difficult and costly to make fresh water from sea water. This is done in a few countries, but the fresh water is for drinking. There is not enough at present for irrigation. Perhaps a scientist will one day invent a cheaper way of producing fresh water from the sea.
【小题1】The first paragraph mainly talks about .
A.the problems caused by river water |
B.the necessity to irrigate the field |
C.the water shortage in some countries |
D.the canals carrying water to fields |
A.to cover the houses and fields |
B.for people to have the right amount of water at all times |
C.to grow crops better |
D.to form a large lake |
A.a dam will be built across the river |
B.a dam will store water for dry seasons |
C.in wet seasons a dam will prevent the flooding of the land |
D.houses and fields will be covered will water |
A.modern dams are made of concrete |
B.Romans once built many great dams |
C.there was too much water in 1rap in the past |
D.modern dams are better than early dams |