题目内容：

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Kenya is the first country to try and protect elephants by text message. Mobile phone SIM cards inserted in the collars(项圈) of elephants automatically send a text message when they get too close to farms, allowing wildlife workers to drive them off rather than shoot them.

Hungry elephants cause big problem for farmers and villagers in some parts of Kenya looking for food and destroying homes and livelihoods in the process. Two years ago the Kenyan wildlife service had to shoot five elephants with regret and sadness who continued to destroy crops.

In an attempt to avoid such destructive actions the Save the Elephants charity installed a mobile phone SIM card in a collar that was placed on a huge bull elephant called Kimani. The conservationists( 自然环境保护者) then set up a virtual fence using a global positioning system.

Each time Kimani came near the fence, a text message was sent to workers. So far he has been prevented from going into farms fifteen times.

The project is expensive requiring five full time staff and a vehicle but it seems to be working successfully as Kimani hasn't come near a farm for four months. A similar system has now been carried out in another part of the country.

One of the biggest benefits of the project is that elephants seem to learn from one another.

Tracking and controlling one elephant can help a whole group change their habits.

The elephants can also be tracked using Google Earth software. This is also helping to prevent illegal hunting and killing as the workers know where to concentrate their resources to best protect the animals.

45. Which of the following is NOT a benefit of the project?

A. To extend elephants' habitat.       

B. To protect farms from being destroyed.

C. To make more elephants change their habits. 

D. To prevent elephants from being shot.

46. The fence mentioned in Paragraph 3 __________________________________ _.

A. can be seen by elephants          B. actually refers to the text message

C. has prevented Kimani for 50 times    D. doesn't exist in fact

47. According to the passage, the project ____________________.

A. costs just a little                       B. is carried out all by machine

C. seems to work out well                 D. is carried out across Kenya