单选题The city has changed a lot It is加longer _____it was ten years ago.

单选题 Thanks to Science, You Can Eat an Apple Every Day A. Walk into a U.S. supermarket on any given day and you're pretty much guaranteed to find apples. In our globalized economy, we expect nothing less than to be able to consume our favorite fruits and vegetables all year, even when they're not in season locally. Placing strawberries from Mexico in your shopping cart in February and stocking up on kiwis (猕猴桃) from Chile in July—that's pretty much normal, even expected. B. But to buy an apple in March? That's a whole different story. We rarely need to go overseas for that. Only 5 percent of the apples consumed in the U.S. are imported, according to the U.S. Apple Association. That means most of our apples are picked from trees in Washington, New York, or Michigan—three of the country's largest apple-producing states—and they are picked during fall harvest. C. Harvest season for apples in the U.S. depends on the variety and the state, falling somewhere between early August and mid-November. So if it's March, your apple was likely harvested months ago. Yet it still tastes pretty fresh. This wasn't always the case. 'It's something we take for granted now,' says Chris Watkins, a professor of horticulture (园艺) at Cornell University and the director of Cornell's cooperative extension. During harvest season, Watkins and post-doctoral students drive a truck to farms all over New York State to collect apples and bring them back to their lab at Cornell. There they study how the apples react under different storage conditions. D. According to Watkins, we have a technology called Controlled Atmosphere (CA) storage to thank for being able to eat an apple whenever we please. In CA storage rooms, the temperature, oxygen, carbon dioxide, and humidity levels are adjusted to form hospitable hibernation environments for apples being stored after harvest. The perfect combination of temperature and gases, which differs for each variety, allows apples to stay fresh for longer after harvest than if they were simply refrigerated. Commercially refrigerating apples only preserves the fruit for a few months before it gets soft and dehydrated. And just keeping them in your home refrigerator? They'll likely only stay fresh for a few weeks. E. The concept of controlled atmosphere storage is not entirely new—modified atmosphere storage for food dates back to the 1800s. But the motivation of research for the facilities that we have today came from Cambridge University in the 1920s. The technique was improved when Robert Smock, a researcher in Cornell University, visited Cambridge in the late 1930s to observe the groundbreaking CA technology developed there. Smock, who studied post-harvest technologies for apples, pears, plums, and peaches, was trying to figure out how to extend the shelf life of the fruits. Smock brought what he learned back to New York and adapted CA to work for local apple varieties, focusing on how to make apples last until the spring. In his laboratory half-hidden in a barn near Cornell, Smock experimented by placing apples in sealed rooms at different temperatures and with various mixtures of oxygen and carbon dioxide to see how the fruit would respond. As a result of Smock's work, the first CA rooms in the U.S. were built in New York in the 1950s, and shortly after, the apple consumption season extended to the springtime nationwide. F. Controlled atmosphere is so widespread today that Watkins estimates that almost every apple you see in a grocery store out of season will have been, at some point in its lifetime, subjected to it. 'The apple industry as we know it today would not exist without CA,' Watkins says. G. The Crist family farm in the Hudson Valley, New York, is just one example. Jeff Crist is a fourth-generation apple farmer and storage facility manager at Crist Brothers Orchards. He estimates his family built their first CA storage facility shortly after Smock made his post-harvest research available for commercial use at Cornell, just an hour's drive away. At the orchard, 400,000 apple trees line different patches of the 550-acre property. The Crists grow apples for large retailers and grocery stores east of the Mississippi River from Florida to Maine—think Giant and Costco. H. And their storage facility allows them to get all of these apples to market when there's demand, not just in the fall. The Crists' CA storage facility has 30 rooms, each one 40- by 80-feet with 20-foot-high ceilings. The rooms are sealed with foam panels and lined with modem sliding doors. Each of the 30 controlled-atmosphere rooms can fit a bunch of apples—1,400,000 to be exact. The rooms fill up quickly during harvest time when employees bring in loads from the fields. I. Then, when the doors slide shut, Crist turns on the CA system right from his iPad. With the touch of his finger, he activates the coolers, lowers the oxygen in the room to about 1.5 to 2.5 percent (the oxygen around is about 21 percent), and adjusts the carbon dioxide, essentially putting the apples to sleep. When they're surrounded by less oxygen and more carbon than found in air, apples don't have enough energy to complete the ripening processes, says Jim Mattheis, a researcher at the USDA's Tree Fruit Research Laboratory located in Wenatchee, Washington. That's because like humans, apples breathe, taking in oxygen and releasing carbon dioxide. J. Sleepier apples have slower respiration rates and stay firm, colorful, flavorful and nutritionally dense for longer. The trick is to avoid bringing the oxygen levels too low, otherwise the apples will ferment. But not all apples ripen quite the same way, so figuring out the right way to do CA is kind of like a puzzle. 'Apples are like people—they are not all the same. One recipe for growing doesn't work with all the different varieties, and it's the same in the post-harvest environment,' Mattheis says. Some varieties are notoriously trickier to care for. For example, Honeycrisps are sensitive to low temperatures so you can't put them in cold environments right after they've been harvested. And Fujis don't always react well to high carbon dioxide levels, so you have to monitor them closely. K. With new apple varieties being developed frequently, post-harvest researchers like Watkins and Mattheis are hard at work. In their labs they test out what type of CA environment works best for these newly bred varieties. Then they take their research to growers like Crist so that when they open their CA rooms as the market demands, their apples are good-looking and tasty.

单选题Michael: Hi, mom. I'd like you to meet my girlfriend, Susan Lee. Susan, this is my mother.Susan: How do you do, Mrs. Miller.Mother: How do you do, Susan. I'm glad you can join us. ______.

单选题An open-minded teacher doesn't always ______ one single teaching method.

单选题According to the author, the notion that computers are to blame for the wage gap is

单选题______is forbidden in the meeting-room, but we are allowed in the room for smokers.

单选题(It is said) that Einstein felt (very) (sad) about the application of his theories (onto) the creation of weapons of war.A. It is saidB. veryC. sadD. onto

单选题 Banking is about money; and no other familiar services or commodities arouse such excesses of passion and dislike. Nor is there any other about which more nonsense is talked. The type of thing that comes to mind is not what normally called economics, which is inexact rather than nonsensical, and only in the same way as all scientists are at the point where they try to predict people's behavior and its consequences. Indeed most social sciences and, for example, medicine could probably be described in the same way. However, it is common to hear assertions of the kind 'if you were marooned (孤立无援) on a desert island a few seed potatoes would be more useful to you than a million pounds' as though this proved something important about money except the undeniable fact that it would not be much used to anyone in a situation where very few of us are at all likely to find ourselves. Money in fact is a token, or symbolic object, exchangeable on demand by its holders for goods and services. Its use for this purpose is universal except within a small number of primitive agricultural communities. Money and the price mechanism, i.e., the changes in prices expressed in money terms of different goods and services, are the means by which all modern societies regulate demand and supply for these things. Especially important are the relative changes in price of different goods and services compared with each other. To take random examples: the price of house building has over the past five years risen a good deal faster than that of domestic appliances like refrigerators, but slower than that of motor insurance or French Impressionist paintings. This fact has complex implications for students of the brick industry, trade unionism, town planning, insurance companies, fine art auctions, and politics. Unpacking these implications is what economics is about, but their implications for bankers are quite different. In general, in modern industrialized societies, prices of services or goods produced in a context requiring a high service-content (e.g., a meal in a restaurant) are likely to rise in price more rapidly than goods capable of mass-production on a large scale. It is also a characteristic of highly developed economies that the number of workers employed in service industries tends to rise and that of workers employed in manufacturing to fall. The discomfort this truth causes the big general trade unions as they contrast their own situation with that of the rapidly growing white-collar unions has been an important source of tension in western political life for many years and is likely to remain so for many more.

单选题 AI long ago mastered chess, the Chinese board game Go and even the Rubik's Cube, ______ in just 0.38 seconds.

单选题The new machine failed to ______ the garbage. As a result, the kitchen was filled to bursting with smelly leftovers.

单选题Trying to______wild life is a job that concerns all of us.

单选题My aunt’s business has been doing poorly，but she’s hoping that her__________ will change.

单选题Physical activity through sports can enhance your child’s physical health.Sports can also have a positive effect on his mental health.Sports participation helps children ____21____life skills such as

单选题One of the important properties of a scientific theory is its ability to ______ further research and further thinking about a particular topic. A. invent B. stimulate C. renovate D. advocate

单选题Dominic, the most ______ pupil in class, will go to Harvard to study this September.