Of all my dreams, my least favorite is the one where I'm in a car. It always begins with me driving, but eventually I realize that for some reason I'm sitting in the back seat. I can’t keep the car under control, rushing toward the roadside until, screaming, I wake up.

This is like the passenger experience in Waymo's self-driving cars. You sit in the back seat of a vehicle and watch as the wheel turns itself above an entirely empty driving seat.

''We made you live your nightmare, '' a Waymo staff member joked after I exited one of the company's fully self-driving car, following a quick drive inside its secret testing site. Waymo, a self-driving car company, arranged these rides for 40 journalists at this site.

There were also some demonstrations(演示). We watched as a Waymo car was cut off by a speeding vehicle. Then the employees created a situation in which a pile of moving boxes fell into the street just as another car passed in the opposite direction. Throughout the day, the cars performed impressively, driving with the level of care you might take if you had a wedding cake in the back seat.

During these demonstrations, Waymo gave information about what it was planning to do with these vehicles. The company has laid out four ways that its technology could be made available to the public. But Waymo's CEO, John Krafcik, wouldn’t show which of these was likely to come to market first, or on what kind of timeline.

I can't help but admire that Waymo is succeeding in developing this technology. There are countless possibilities at play on the road. The task of programming software to react to all those situations is unimaginably complex. What a great breakthrough!

Disadvantages of the Cell Phone

There is more than one advantage and disadvantage of cell phones. Anyone considering purchasing their first cell phone, or considering getting rid of their cell phone, should look at the device from different angles. Surely there are disadvantages of buying cell phones. 【小题1】.

Added Costs

【小题2】. First, you will have to purchase a cell phone. While you may find a free phone option with your new wireless plan, smartphone devices can cost as much as $400 or more. Then you will have to pay a monthly fee for service. Service plans vary and can include costs for minutes, text messages, data, and insurance.

【小题3】.

Every time you have your cell phone with you, it could ring and interrupt what you are doing. While it is convenient to keep your phone with you when you are away from home, it also leaves you open to calls from your mother, your boss, or anyone that knows your phone number. This may lead some people to feel like they have less privacy than before.

Less Reliable than a Landline Telephone

【小题4】. This means a cell phone,' no matter how reliable, is not going to work everywhere unlike a landline telephone, which provides service that is more reliable.

Higher Possibility of Accidents

If you are talking or texting on your cell phone while you are driving, you are far more likely to be involved in a car accident. 【小题5】. And despite several recently imposed （强制实行的） laws banning cell phone use while people are driving, many find them almost impossible to carry out.

As the saying goes, time is money. And in my opinion, time is even precious than money. Why? Because when money is spent, we still have a chance to earn them back. But when time is wasting, we can never get it back. There is no doubt whether time is very limited, and even a minute is of great value. We should make fully use of time to do what should be done. It’s the pity that a lot of people still didn’t appreciate the value of time. They are wasting their time doing nothing of useful. We should form the good habit of race against time and make a difference in our world.