已知点A(3,1)是直线l被双曲线x24-y23=1所截得的弦的中点,则直线l的

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问题:

已知点A(3,1)是直线l被双曲线
x2
4
-
y2
3
=1
所截得的弦的中点,则直线l的方程是(  )
A.9x-4y-23=0B.9x+4y-31=0C.x-4y+1=0D.x+4y-7=0
考点:圆锥曲线综合
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简述胃癌的药物止痛方法

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下列叙述中正确的是______。

A.线性表是线性结构

B.栈与队列是非线性结构

C.线性链表是非线性结构

D.二叉树是线性结构

题型:选择题

阅读理解。

     People realize that, although animals may not have the same intelligence as human beings, they are clever

enough to learn certain things.

     Dogs are extremely useful as companions for blind people. When a dog has been properly trained, he will

always lead his blind master (主人) in the right direction and keep him out of danger. For example, seeing-eye

dogs learn never to cross a busy road when cars are coming, even if their master ordered them to do so.

     Horses are also able to learn many things. Horses that are used for guard or police duty must learn never

to be frightened of noises and traffic. Racing horses are able to run much faster than other horses, but they

are also quite high strung (紧张). Therefore, it is necessary for those people who train them to be very patient

(耐心) and understanding.

     The movie and television can use trained animals too. Some animals, such as monkeys and foxes, are easy

to film. All you have to do is make a trail in front of the camera by putting something that smells good to the

animals over the ground. Big animals, such as lions and tigers, can be photographed as they come happily back

to their families or dinner. If a movie actor is nearby, the well-trained animal will pay no attention to him.

However, the audience may imagine that the actor escaped a terrible death.

1. Seeing-eye dogs have to learn the following except _____.[ ]

A. following the master's order anytime

B. leading their master in the right direction

C. keeping their master safe while leading the way

D. crossing a busy road at the proper time

2. What does "make a trail" mean here in the last paragraph? [ ]

A. place something to attract the animal

B. give the animal a certain task

C. order the animal to do things

D. follow the animal to hunt

3. Lions can be photographed easily when _____. [ ]

A. they are following a trail of something that smells good

B. they are returning to their families

C. they have been trained to work with other animals

D. they do not know a movie-actor is nearby

4. Which of the following statements is the main idea of the passage? [ ]

A. Dangerous wild animals can be trained.

B. Dogs can be trained to help blind people.

C. Animals can be trained to learn certain things.

D. Animals can become interested in learning.

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突发事件或者旅游安全事故发生后,旅游经营者应当怎么做?

题型:选择题

下列引起嗜酸粒细胞增多的疾病中属变态反应性疾病的是

A.湿疹

B.荨麻疹

C.结节性多动脉炎

D.高嗜酸粒细胞综合征

E.猩红热

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