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问题 填空题

减弱噪声的方法有很多种，可以在声源处、传播过程中、接收处减弱噪声．请在下列横线上填上减弱噪声的措施：“掩耳盗铃”是在______减弱噪声；摩托车加上消音器是在______减弱噪声；把门窗关上，是在______减弱噪声；城区禁止机动车鸣喇叭，是在______减弱噪声．

答案

掩耳盗铃是在接收处减弱噪声；摩托车加上消声器，城区禁止机动车鸣喇叭是在声源处减弱噪声；把门窗关上是在传播过程中减弱噪声．

故答案为：接收处，声源处，传播过程中，声源处．

单项选择题

In the second half of each year, many powerful storms are born in the tropical Atlantic and Caribbean seas. Of (91) , only about half a dozen (92) the p, circling winds of 75 miles per hour or more that give them hurricane status, and several usually (93) their way to the coast. There cause millions of dollars of (94) , and bring death to (95) numbers of people.
The great storms that hit the coast start (96) innocent circling disturbances hundreds, even thousands of miles out to sea. As they travel aimlessly over water (97) by the summer sun, they are carried westward by the (98) winds. When conditions are just (99) , warm, moist air flows in (100) the bottom of such a disturbance, moves upward through it and comes out at the top. In the (101) , the moisture in this warm air produces rain, and with it the heat is converted to energy in the form of p winds. As the heat increases, the (102) hurricane begins to swirl in a counter-clockwise motion.
The average life of a hurricane is only about nine days, but it contains almost (103) power than we can imagine. The energy in the heat released by a hurricane’s rainfall in a(n) (104) day would (105) the entire electrical needs of the United States for more than six months. Water, not wind, is the main (106) of death and destruction in a hurricane. A(n) (107) hurricane brings 6-to 12-inch downpours (108) in sudden floods. (109) is the powerful movement of the sea-the mountains of water moving toward the low-pressure hurricane center. The water level (110) as much as 15 feet above normal as it moves toward shore.

A．coming

B．creating

C．producing

D．resulting
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多项选择题

采煤机液压油乳化的原因是以下（）

A、冷却器漏水

B、吸入湿空气

C、油位过低

D、滤油器堵塞
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