per是什么意思？

On February 14th, the self-driving car, travelling at 2 miles per hour, pulled out in front of a public bus going 15 miles per hour.

The report warns that 200 million poor workers are at risk of joining the ranks of people living on less than two dollars per day in the past three years.

If we replaced half of our administrative staff with classroom teachers, we might actually get a majority of our classes back to 20 or fewer students per teacher.

But this doesn't necessarily translate to real cooking, and the result of this survey shouldn't surprise anyone: 52% of those 65 or older cook at home five or more times per week; only a third of young people do.

And although you don't read about this much, the United States is also a large exporter of oil products, selling about 2 million barrels of petroleum products per day to about 90 countries.

Marriott had its worst quarter ever, with revenues per room falling by 25%.

billion in American high schools, helping to open about 1,000 small schools-most of them with about 400 kids each with an average enrollment of only 150 per grade, About 500 more are on the drawing board.

Houses built before 1939 use about 50% more energy per square foot than those built after 2000, mainly due to the tiny cracks and gaps that expand over time and let in more outside air.

Caught in the Web A few months ago, it wasn't unusual for 47-year-old Carla Toebe to spend 15 hours per day online

In Lagos, foreign oil workers can pay as much as $65,000 per year in rent for a modest apartment in a safe part of town.

That’s the conclusion of a recently released study, which analysed 259 bottles from 11 brands sold in nine countries, revealing an average of 325 plastic particles per litre of water.

The fifth largest city in US passed a significant soda tax proposal that will levy 1.5 cents per liquid ounce on distributors.

2 million barrels per day to the crude oil market, contributing to a global over-supply.

With fertilizer prices jumping nearly 50% per metric ton over the last year in some places, human waste is an attractive, and often necessary, alternative.

Today, energy storage is a $33 billion global industry that generates nearly 100 gigawatt-hours of electricity per year.

These less- stressed workers gained an average of 62 minutes per week of productivity.

Recent polls by the Pew Research Centre in Washington, DC, found that 75-80 per cent of participants regarded climate change as an important issue.

Per-capita local government spendingIn other words, communities with high levels of per-capita income growth, high percentages of two-parent families, and high local government spending—which may stand for good schools— are the most likely to help poor children relive Horatio Alger's rags-to-riches story.

Per-capita ( ' , 人均 ) income growth 2.

For a middle-class, husband-and-wife family (average pretax income in 2009: $76,250), spending per child is about $12,000 a year

Today, we produce about four billion metric tonnes of food per year

trillion m3of water is used by humans per year.

Let's see, Group C, three to five days hire with unlimited mileage is 53 pounds per day.

For Group C cars is 6 pounds per day

We can invent computers capable of processing ten million calculations per second.

The price is ￡60 per person including a continental breakfast.

Parking rates will be attracted about $400 monthly or $25 per day, according to Ari Milstein, the director of planning for Automation Parking Systems, which is the U.S. subsidiary of a German company.

I always tell people to make sure they're drinking enough fluids, which for the average person is 60 to 70 ounces a day, which translates into eight 8-ounce glasses of water or liquid per day.

In 2005, as the authors observe, real consumption per person in France was only 60% as high as the U.S., making it appear that Americans were economically much better off than the French on average.

It reproduces incredibly quickly, breeding up to 12 generations per year if conditions are favorable.

Mothers who slept in the same room as their infants, whether in the same bed or just the same room, had poorer sleep than mothers whose babies slept elsewhere in the house: They woke up more frequently, were awake approximately 20 minutes longer per night

Participants in the study were separated into two groups—one group was asked to eat 30 grams of protein per meal in the form of whole foods.

Resurrection plants, defined as those capable of recovering from holding less than 0.1 grams of water per gram of dry mass, are different.

The advent of new technologies has added about 4.2 million barrels per day to the crude oil market, contributing to a global over-supply.

The bird Clark's nutcracker, for example, hides up to 100, 000 seeds per year, up to 30 kilometers away from the seed source, and has a very close symbiotic(共生的) relationship with several pine species, most 32 notably the whitebark pine.

These less-stressed workers gained an average of 62 minutes per week of productivity.

Those spending 10-19 hours per week on their devices were 41 percent more likely to be unhappy than lower-frequency users.

Today, energy storage is a $33 billion global industry that generates nearly 100 gigawatt-hours of electricity per year.

When Liu, the UCLA sleep researcher and professor of medicine, brought chronically sleep-restricted people into the lab for a weekend of sleep during which they logged about 10 hours per night, they showed improvements in the ability of insulin to process

While by no means perfect, it is considerably more comprehensive than average income, taking into account not only growth in consumption per person but also changes in working time, life expectancy, and inequality.

with fertilizer prices jumping nearly 50% per metric ton over the last year in some places, human waste is an attractive, and often necessary, alternative.