英语四级听力难度相对来说比较简答，语速跟VOA慢速英语差不多。为了帮助同学们提高英语四级听力，小编特意整理了2014年12月英语四级听力练习:VOA慢速英语，供各位考生参考，希望大家多多练习。
From VOA Learning English, this is the Technology Report.
A fly with an extremely unusual ability to hear is the model for what may be the future of new and improved hearing aids. The insect behaves like a parasite -- an organism that lives on or in another organism called a host. This exceptional fly places larvae -- a young fly onto a cricket host. The larvae digs into the cricket and eats the insect from the inside out.
The tiny yellow fly lives in Central America and the southern United States. It finds its host by listening for the cricket's high chirping voice. The fly can easily find a cricket from as far away as 91 meters.
Neal Hall is a sound engineer who worked on the new hearing aid model. He says the fly's behavior is very strange. Mr. Hall and his team at the University of Texas made a copy of the fly's hearing structure.
"And they discovered that the fly has a clever mechanism that instead of using two independent ears, like a human would, the fly's ears are actually coupled," says Hall.
The fly's ears are two millimeters apart. That distance is so small, that sound reaches one ear just four millionths of a second before arriving at the other. Experts say it should be impossible to identify where a sound is coming from. But inside this fly's ear is a 1.5 millimeters long structure similar to a see-saw -- a piece of children's party equipment.
Like the see-saw, the fly's ear structure goes up and down from a central point. Pressure waves against the structure increase the time it takes for sound to travel and permit the fly to find its host.
Mr. Hall and his team used the chemical element silicon to copy the fly's ear structure. They also used special electric materials that enable them to measure its movements at the same time.
Hall says the hearing aid device could be used in two ways. One way would be to help the military on the battle field, there, sensors could find where shots are coming from. The second way would be to remove unwanted noise from a person's surroundings.
"That is a feature that is incredibly useful for hearing aids, for example, where right now, if you turn up the gain of a hearing aid or turn up the volume to hear someone across from you, it also amplifies everything else in the room," said Hall.
Hall says the next test in marketing the hearing aid device is to make it usable. He says the device must be handled carefully because it is so small. He notes that the fly does not have this concern.
And that's the VOA Learning English Technology Report. I'm Jonathan Evans.
词汇讲解：
1. improve vt.提高(土地、地产)的价值; 利用(机会); 改善，改良
例句：We can improve quality, reliability, and durability.
我们可以提高质量、可靠性和耐久性。
2. structure vt.构成，排列
例句：Many people view structure as restrictive, something that inhibits spontaneity.
许多人把组织构建视为限制，会限制自发性的东西。
3. identify vt.识别，认出
例句：It aims to identify the characteristic value of aesthetically satisfying objects.
它的目的在于鉴别审美快感的物体所特有的价值。
4. permit vt.许可，准许
例句：He did not normally permit himself the indulgence of sentiment.
他一般不允许自己陷入感情的罗网。
5. remove vt.开除; 去除; 脱掉
例句：Drugs remove man from the treadmill of routine.
药物可以使人摆脱日常单调的工作带来的疲劳。
6. concern vt.涉及，关系到
例句：The situation caused serious concern to the Government.
局势引起政府的极大关注。
短语讲解：
1. The larvae digs into the cricket and eats the insect from the inside out.
dig into 挖掘; 把…戳进…; 调查; 刻苦钻研
例句：I'll dig into these issues in my next post.
我将在下一篇文章中深入探讨这些问题。
2. And they discovered that the fly has a clever mechanism that instead of using two independent ears, like a human would, the fly's ears are actually coupled," says Hall.
instead of (用…)代替…， (是…)而不是
例句：Use household products instead of commercial cleaners.
让日常用品代替商业清洁品。
3. Like the see-saw, the fly's ear structure goes up and down from a central point.
up and down 上上下下; 起落
例句：Children like bouncing up and down on a sofa.
孩子们喜欢在沙发上蹦蹦跳跳。
4. They also used special electric materials that enable them to measure its movements at the same time.
at the same time 同时; 一起; 但是
例句：At the same time, infrastructure investment is growing.
与此同时，基础设施的投资也在增加。
5. One way would be to help the military on the battle field, there, sensors could find where shots are coming from.
come from 来自
例句：Ambient noise may come from any direction.
外界噪声可以来自任意方向。
6. "That is a feature that is incredibly useful for hearing aids, for example, where right now, if you turn up the gain of a hearing aid or turn up the volume to hear someone across from you, it also amplifies everything else in the room," said Hall.
turn up 开大; 翻起; 出现
例句："Turn up your radio, please."
请你把收音机开响一点儿。