4 . Some scientists say that animals in the oceans are increasingly threatened by noise pollution caused by human beings.

The noise that affects sea creatures comes from a number of human activities. It is caused mainly by industrial underwater explosions, ocean drilling, and ship engines. Such noises are added to natural sounds. These sounds include the breaking of ice fields, underwater earthquakes, and sounds made by animals themselves.

Decibels (分贝) measured in water are different from those measured on land. A noise of one hundred and twenty decibels on land causes pain to human ears. In water, a decibel level of one hundred and ninety-five would have the same effect.

Some scientists have proposed setting a noise limit of one hundred and twenty decibels in oceans. They have observed that noises at that level can frighten and confuse whales.

A team of American and Canadian scientists discovered that louder noises can seriously injure some animals. The research team found that powerful underwater explosions were causing whales in the area to lose their hearing. This seriously affected the whales' ability to exchange information and find their way. Some of the whales even died. The explosions had caused their ears to bleed and become infected.

Many researchers whose work depends on ocean sounds object to a limit of one hundred and twenty decibels. They say such a limit would mean an end to important industrial and scientific research.

Scientists do not know how much and what kinds of noises are harmful to ocean animals. However, many scientists suspect that noise is a greater danger than they believed. They want to prevent noises from harming creatures in the ocean.

5 . Your next car might drive itself. After years of trials on city streets, driverless vehicles are now nearing the production phase. Last month, a driverless bus began carrying passengers through Lyon, France. Most in the automobile industry think self-driving vehicles will be on the road by 2020 or before.

Driverless cars will at first be huddled with human-driven cars. But the first places where they will become dominant（占支配地位的）are dense urban areas-precisely the spots most damaged by the automobile age. Many advanced cities are already reducing the role of human-driven cars. Driverless cars will quicken that process and will bring us great benefits.

Driverless cars will reduce accidents by around 90 percent. That's big-the annual death toll on the world's roads is about 1.2 million a year. Pollution and carbon emissions will drop, because urban driverless cars will be electric. The old, otherwise they would stay at home most of the time and the disabled and teenagers will suddenly gain mobility.

On the other hand, driverless cars will bring catastrophe（灾难）.The best thing about the automobile age is that it employs tens of millions of people to make, market, insure and drive vehicles. Over the next 20 years, most men who now drive trucks, taxis and buses will see their jobs reduced. Carmakers are especially scared. A few cars in the future might be made by tech companies such as Apple, Baidu and Google. Imaging the impact on Germany, where the automotive sector is the largest industry.

Dramatic change is coming, and driverless cars could arrive by 2020. But governments have hardly begun thinking about it. Only 6 percent of the biggest US cities have factored them into their long-term planning.

A decade ago anyone hardly saw the smartphone coming. It has brought an epidemic of mass addiction. Let's hope we do a better job of handling the driverless car.