The new law represents recent and current requirements for new food additives and new active______for food products.

A.ingredients

B.constituents

C.elements

D.components

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Once again, this assumption is implausible.The public will not be outraged if it is told that precedents will be confined to their facts.

A.unreasonable

B.unbelievable

C.improbable

D.insuperable

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The current confrontation feels weightier.One reason is why China, which once merely seemed to be catching up, now wants to overtake.

A.because of China

B.since China

C.because China

D.that China

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In December, Waymo LLC, the leading driverless car company, brought out the world's first commercial robo-taxi service.But for now, the service is only available to about 400 test families in suburban Phoenix, and each of its converted Chrysler minivans still has a person at the wheel in case anything goes awry.
“It's a pretty glaring indication that we're not there yet，” says Matthew Johnson- Roberson, co-director of the University of Michigan's Ford Center for Autonomous Vehicles, who's working with automakers to develop robot rides.Waymo, owned by Google parent Alphabet Inc.and recently valued at $250 billion by Jefferies Research LLC, declined to comment.In a blog post, Chief Executive Officer John Krafcik said the human safety drivers were at work in Arizona to make riders feel more comfortable.
Waymo's timid rollout is the latest speed bump for a technology touted as certain to save the world from road deaths.As auto and tech giants converge on Las Vegas for the consumer electronics show known as CES，which formally kicks off on Jan.8 and includes a keynote from Krafcik, the seemingly boundless optimism that surrounded driverless cars only a few years ago has been tempered by a slew of persistent technological challenges and big questions about near-term business models, especially as a recession looms.4tMost of the automakers are chasing a business model that has yet to be proven — that elusive robo-taxi.” says Craig Giffi, head of consulting firm Deloitte's U.S.automotive and industrial products practice.
At CES, driverless and auto technology will cover 300,000 square feet of floor space, more than the total size of many stand-alone car shows，and the auto industry is continuing to pour billions into self-driving cars.Ford Motor Co.CEO Jim Hackett said in November that the market for autonomous vehicles and other mobility services could reach $10 trillion — half the size of U.S.gross domestic product.Annual sales of self-drivers will hit 33 million by 2040 and account for more than a quarter of global vehicle deliveries, according to researcher IHS Markit.
That's why automakers and tech companies are rushing to get robots on the road.General Motors Co.'s Cruise Automation plans to debut its automated ride-hailing business in a U.S.city in 2019, and Ford promises to deploy tens of thousands of self-drivers on the streets of multiple U.S.cities in 2021 as part of a profitable business moving people and packages.Even Uber resumed testing its autonomous Volvos in December, only nine months after one struck and killed a pedestrian in Tempe, Ariz.
But a study from Deloitte suggests things will move more slowly than expected.Half of the 25,000 consumers Deloitte surveyed globally said they didn't believe autonomous vehicles would be safe, up slightly from 47 percent a year ago.Just 39 percent of them trust automakers to bring the technology to market.Most surprising: Only 12 percent of U.S.consumers reported using services such as Uber and Lyft once a week, half the rate of a year ago.Taken together, the findings undermine the near-term business case for the robo-taxi,which relies on an ever-growing pool of consumers ditching their cars.
As long as human safety drivers are required, profits are out the window.“The economics of that don't work out at all，” says Johnson-Roberson，the University of Michigan technologist.He says the only way to remove safety drivers is to isolate autonomous cars in their own lanes, walled off from unpredictable humans.Among other things, driverless cars still struggle to merge into traffic.

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How much physical activity should teenagers do,
and how can they get enough?
Many teenagers spend a lot of time being sedentary (sitting or lying down) at school or work during their______(91) time.Modem______(92) such as smart phones，computers and food delivered to your front door encourage sedentary behavior.But this lack of physical activity can have______(93) consequences for your physical and mental health.
We have all probably been told we have to exercise to stay healthy, but how much physical activity is the right amount for teenagers? And what are the______(94)?
All teenagers are______(95) to do 60 minutes of physical activity each day.There are numerous benefits of physical activity, including physical (improved fitness and decreased risk of illness), social (having fun with friends) and______(96) (helps manage stress and anxiety) benefits.
You should try to include a combination of______(97) activities (such as swimming or walking)，strength training (such as sit ups or weight training) and flexibility training (such as yoga or stretching).
Try to______(98) easy, moderate, and harder activities that are both fun and personally challenging.Limiting______(99) time and screen time by regularly______(100) periods of sedentary behavior is another good idea.For example,standing and moving for a few minutes after every hour of sitting.
There are 1,440 minutes in every day,______(101) being physically active for just 60 minutes is easily achievable.
Incidental activity______(102) to any movement that increases your level of daily activity.These activities don't happen at the______(103), but instead rely on your daily choices.
For example, office workers are often told to get more activity into their day by doing things such as parking further away from work and walking the rest of the way，and using the______(104) instead of the lift.
Similarly, you could:
①walk or ride to school instead of taking a car or bus;
②walk around the oval as you chat to your friends at lunchtime instead of sitting;
③do something______(105) when you meet up with your friends on the weekend,such as swimming at the beach;
④do an (a)______(106) lap when you go to the shopping centre and/or, go down every aisle when you go to the supermarket;
⑤at family gatherings, play games with your younger siblings and cousins rather than playing on your phone;
⑥take your dog for a walk and a play at the park more often;
⑦ride an exercise bike or do some stretching while you watch TV.
Making these simple choices each day can become a habit______(107) increases your physical activity and improves your health.______(108) activity doesn't replace planned exercise, but all the activity you do during the day adds up, and these two forms of activity can work together to increase your physical activity level.
Incidental activity requires no special______(109) or preparation.You can just stand up and move at any time you choose.Remember: something is better than ______(110) and more is better than less.

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