问题 解答题

保定辖区的一些瓜农,利用日光塑料大棚栽培种植了品种繁多的优质西瓜,获得了较好的经济效益.

(1)大棚西瓜能够提前上市,主要是克服了______对植物生长的影响;西瓜内有多粒种子,这说明子房内含有多个______.

(2)切西瓜时会流出汁液,汁液主要存在于细胞的______里,汁液中含有多种营养物质.

(3)种植西瓜时需要合理密植,这主要是为了提高______的效率.

答案

(1)冬天,温度低,不适合西瓜等植物的生长,但是如果利用大棚可以提高温度,能使西瓜提早上市,可见大棚克服了温度对植物生长的影响;种子是由胚珠发育成,西瓜内有多粒种子,这说明其子房内含有多个胚珠.

(2)液泡里含有细胞液,含有各种有味道的物质,以及营养物质等,如西瓜的汁液中含有大量的营养物质,有甜味,就是位于液泡中,

(3)合理密植是指在单位面积上,栽种作物或树木时密度要适当,行株距要合理.合理密植是增加作物产量的重要措施.通过调节植物单位面积内个体与群体之间的关系,使个体发育健壮,群体生长协调,达到高产的目的.合理密植,有利于充分利用光能,提高光合作用的效率.种植过密,植物叶片相互遮盖,只有上部叶片进行光合作用,种植过稀,部分光能得不到利用,光能利用率低.只有合理密植才是最经济的做法.

故答案为:(1)气温; 胚珠     (2)液泡     (3)光合作用

阅读理解

The illegal ivory(象牙) trade has been a major problem in Africa for decades. Poachers have killed hundreds of thousands of elephants to obtain ivory. Now, affected areas are taking action. The International Union for Conservation of Nature (IUCN) announced on Wednesday key African states where poaching takes place have promised to stop the ivory trade to protect elephants.

Over the past few days, top officials and experts from 30 states met at the African Elephant Summit. The conference, organized by the IUCN and the government of Botswana, was held in Gaborone, Botswana.

Conservation efforts will include China and Thailand, where much of the ivory is sent. “Now is the time for Africa and Asia to join forces to protect this universally valued species,” said Botswana President Ian Khama.

In the 1980s, as many as 1 million elephants across Africa were killed for their ivory. The ivory was used to make jewelry and other items. This continued until 1989, when the Convention on International Trade in Endangered Species (CITES) voted to ban all the trade in ivory. As a result, demand for ivory fell. Governments cracked down on poachers. Elephant populations slowly began to increase. However , this progress was short-lived.

According to the IUCN, 2011 saw the highest levels of poaching and illegal ivory trading in at least 16 years. Around 25,000 elephants were killed in Africa that year. Data from the IUCN  show even higher levels of illegal trade may have been reached in 2013. “With an estimated 22,000 elephants illegally killed in 2012, we continue to face a critical situation,” said John E. Scanlon, CITES Secretary-General. “Current elephant poaching in Africa remains far too high, and could soon lead to local extinction if the present killing rate continues.

At the African Elephant Summit , key African states where elephants make their home agreed to develop a “zerotolerance approach” to poaching. The deal calls for maximum sentences for poachers and hunters, and increased cooperation between affected states. Officials are committed to classifying wildlife trafficking (交易) as a serious crime --- and to making sure that the people who commit it are punished. All participants at the conference agreed to sign the deal. With these states working together, there may yet be hope for elephants.

小题1:The purpose of holding the African Elephant Summit is to _________.

A.make new laws to punish poachers.

B.prevent elephants from being poached.

C.collect money for elephants’ protection

D.call for African countries to save elephants.小题2:Why are China and Thailand mentioned in the text?

A.The ivory is illegally sold in these two countries.

B.Elephants need protecting in these two countries.

C.They know how to protect wildlife like elephants.

D.They prefer jewelry and other items made of ivory.小题3:What can we learn from Paragraph 5 ?

A.The governments do nothing to protect animals.

B.Elephant poaching in Africa is out of control.

C.A large number of elephants have been killed.

D.Illegal ivory trading is to blame for the elephants’ extinction.小题4:What would be the best title for the text?

A.Wild Animals Are at Risk

B.New Hope for Elephants

C.Elephants Need Our Help

D.Wildlife Protection in Africa

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