广播电视开展经营创收主要依托媒体本身的资源，开展的活动一般与______无关。

文物是研究历史的重要物证，下列对图中信息理解正确的是

A．工业“大跃进”时期以股息发放工资

B．资本主义工商业改造采取公私合营政策

C．人民公社社员按期领取生产贷款

D．手工业者以入股形式参加生产合作社

阅读理解。

     Not long ago, an airplane was flying over New Zealand. There was a television camera crew on board.

Suddenly, out in the night sky, a bright sphere came into view. Everyone on board saw it and everyone

thought, "UFO"-Unidentified Flying Object (不明飞行物). The camera crew went into action and started

filming. That week people all over the world saw the film of this mysterious light on their television screens.

What was it? Was it a spaceship full of visitors from another planet? The captain of the aeroplane and the

film crew believed it was. Other observers had many different explanation. Some said it was Venus. Others

said it was just a trick of light.

     An air traffic controller (机场导航员) also saw it on his radar screen. He thought that a flock of birds

was causing dots on his radar screen when the "UFO" appeared.

     Most astronomers now believe that what these people saw was almost certainly the planet Venus. At that

time of year it is very bright and easy to see. And from a more aeroplane it can appear to be moving fast. So

far there is no proof that UFOs or spaceships from other planets do exist. These years investigators of UFOs

here investigated thousands of sightings-or occasions when people said they saw a UFO. Ninety percent of

these turned out to have a simple explanation.

     However, it's a good idea to keep an open mind. Scientists in some countries are trying to persuade their

governments to help them study UFOs. And they are planning to co-operate internationally on reporting and

investigating sightings of UFOs.

     After all, it is quite possible that there is life out there in the universe. And if something is alive, it is quite

possible that it will come to visit us.

1. So far there is no proof that _____. [ ]

A. UFOs are just a trick of light

B. UFOs are aeroplanes from the planet Venus

C. there are UFOs or spaceships from outer space

D. other planets exist

2. Scientists in many countries _____. [ ]

A. have investigated that UFOs are spaceships from other planets

B. are helping their governments study UFOs

C. are planning to co-operate internationally in the study of UFOs

D. believe that there is certainly life on the other planets

3. Which one of the following statements is true according to the passage? [ ]

A. People didn't see the film of that mysterious light on their television screens.

B. These years investigators of UFOs have simply explained most of sightings-or occasions when people 

     said they saw a UFO.

C. Life out there in the universe does exist.

D. Even if there is life on the other planets it will not visit us.

4. In the last paragraph, "something" probably refers to _____. [ ]

A. a certain thing that scientists are studying

B. an imaginary man

C. an animal

D. intelligent life

市场经济是自由的经济、平等的经济、产权明晰的经济，是市场交换规则普遍化的经济。

同步电动机发出不正常的响声，产生机械脉振其原因可能是（）

A.电网电压低，“SBZ失步再整定”可控硅装置失控。

B.励磁电压高或失步。

C.机械负荷过重。

在相同的电流强度条件下，就致人死亡的可能性大小而言，最危险的电流是( )。

A．工频电流
B．高频电流
C．直流电流
D．冲击电流