英译汉：frequency

频度(frequency)

The United States experienced some of the most extreme weather events in its history this spring, including deadly outbreaks of tornadoes, near-record flooding, drought and wildfires. Damages from these disasters have already passed $ 32 billion, and the hurricane season, which is just beginning, is projected to be above average, according to the National Oceanic and Atmospheric Administration.
Government scientists said Wednesday that the frequency of extreme weather has increased over the past two decades, in part as a result of global warming caused by the accumulation of carbon dioxide in the atmosphere. But they were careful not to blame humans for this year’s rash of deadly events, saying that in some ways weather patterns were returning to those seen at the beginning of the last century. "Looking at long-term patterns since 1980, indeed, extreme climatological and meteorological events have increased," said Thomas R. Karl, director of NOAA’s National Climatic Data Center. "But in the early part of the 20th century, there was also a tendency for more extreme events followed by a quiet couple of decades. "
Presenting a new NOAA report on 2011 extreme weather, Dr. Karl said that extremes of precipitation have increased as the planet warms and more water evaporates from the oceans. He also said models suggest that as carbon dioxide builds up in the atmosphere and heats the planet, droughts will increase in frequency and intensity. "But it is difficult and unlikely to discern a human fingerprint, if there is one, on the drought record of the United States," he said.
Some other climate scientists were more categorical about the human contribution to extreme climate events. Kevin Trenberth, distinguished senior scientist at the National Center for Atmospheric Research, said that when the greenhouse effect caused by burning fossil fuels is added to the natural variability of climate, weather disasters can be expected to occur more frequently. "Global warming is contributing to an increased incidence of extreme weather because the environment in which all storms form has changed from human activities," Dr. Trenberth said in a telephone interview Wednesday. "Records are not just broken, they are smashed. It is as clear a warning as we are going to get about prospects for the future. "
April was a particularly devastating month for tornadoes and rainfall, with 875 tornadoes reported during the month and heavy rain and snowmelt contributing to Mississippi River flooding later in the spring that surpassed the historic floods of 1927 and 1937. So far this year, there have been nearly 1,400 preliminary tornado reports nationwide; those reports will most likely be whittled down to about 900 confirmed tornadoes, the second-highest annual total recorded in modern times. The record is 1,011 confirmed tornadoes in 2008. The year also is on track to be one of the deadliest, with 536 fatalities so far from tornadoes, placing 2011 in sixth place in United States history and the deadliest since 1936.

Those who blame human activities attribute heightened extreme weather to（）

A:the natural climatological and meteorological variability B:the increased frequency and intensity of storms and droughts C:the higher levels of carbon dioxide in the atmosphere D:the global warming caused by evaporation from the ocean

A commonplace in genetics is the relationship between recombination frequency and crossover value. Generally speaking, ______.

A:recombination frequency may be directly obtained according to phenotypic ratios, but crossover value cannot be directly obtained according to phenotypic ratios B:crossover value may be replaced by recombination frequency or chiasm frequency you get from the observation under microscope when genetic distance is considerably short C:crossover value may be replaced by recombination frequency when genetic distance is as a medium value, not too long and not too short D:recombination frequency will be very different from crossover value when there is a third locus in between the two loci you analysed

Passage Four
Unwanted sound, or noise, such as that produced by airplanes, traffic, or industrial machinery, is considered a form of pollution. Noise pollution is at its worst in densely populated areas. It can cause hearing loss, stress, high blood pressure, sleep loss, distraction (注意力分散), and lost productivity!
Sounds are produced, by objects that vibrate (振动), at a rate that the ear can detect. This rate is called frequency and is measured in hertz (赫兹), or vibrations per second. Most humans can hear sounds between 20 and 20,000 hertz, while dogs can hear high pitched sounds (高频声音) up to 50,000 hertz. While high frequency sounds tend to be more hazardous (危险的) and more annoying to heating than low frequency sounds, most noise pollution damage is related to the intensity of the sound. Measured in decibels (分贝), noise intensity can range from zero, the quietest sound the human ear can detect, to over 60 decibels. Conversation takes place at around 40 decibels, a subway train is about 80 decibels, and a rock concert is from 80 to 100 decibels. The intensity of a nearby jet taking off is about 110 decibels. 120 decibels axe the limit at which human beings will be aware of pain, and suffer from potential heating loss. Long lasting, high intensity sounds are the most damaging to heating and produce the most stress in humans.
Solutions to noise pollution include adding insulation and sound proofing (隔音) to doors, walls, and ceilings; using ear protection, particularly in industrial working areas; planting vegetation to absorb and screen out noise pollution; and zoning urban areas to maintain a separation between residential areas and zones of excessive noise.

What is most noise pollution damage concerned with（）

A:Objects. B:Intensity. C:Rate. D:Frequency.

Although a given waveform may contain frequencies over a very broad range, as a practical matter any transmission system will be able to accommodate only a limited band of (86) . This, in turn, limits the data rate that can be carried on the transmission (87) A square wave has an infinite number of frequency components and hence an infinite (88) However, the peak amplitude of the kth frequency component, kf, is only l/k, so most of the (89) in this waveform is in the first few frequency components. In general, any digital waveform will have (90) bandwidth. If we attempt to transmit this waveform as a signal over any medium, the transmission system will limit the bandwidth that can be transmitted.

（89）是（）

A:frequency B:energy C:amplitude D:phase

Although a given waveform may contain frequencies over a very broad range, as a practical matter any transmission system will be able to accommodate only a limited band of （1）. This, in turn, limits the data rate that can be carried on the transmission （2）. A square wave has an infinite number of frequency components and hence an infinite （3）. However, the peak amplitude of the kth frequency component, kf, is only l/k, so most of the （4） in this waveform is in the first few frequency components. In general, any digital waveform will have（5） bandwidth. If we attempt to transmit this waveform as a signal over any medium, the transmission system will limit the bandwidth that can be transmitted.

（4）是（）

A:frequency B:energy C:amplitude D:phase

Although a given waveform may contain frequencies over a very broad range, as a practical matter any transmission system will be able to accommodate only a limited band of （） . This, in turn, limits the data rate that can be carried on the transmission （） . A square wave has an infinite number of frequency components and hence an infinite （） .However, the peak amplitude of the kth frequency component, kf, is only 1/k, so most of the （） in this waveform is in the first few frequency components. In general, any digital waveform will have （） bandwidth. If we attempt to transmit this waveform as a signal over any medium, the transmission system will limit the bandwidth that can be transmitted.

so most of the （） in this waveform is in the first few frequency components.

A:frequency B:energy C:amplitude D:phase

Long-Term Evolution (LTE) is a technological standard for wireless mobile broadband networks. LTE will make the use of the latest technologies. Orthogonal ______ Division Multiple Access ( a technology well suited to achieving high peak data rates in high-spectrum bandwidths) will be used on the downlink. On the uplink, LTE will use ______ Carrier Frequency Division Multiple Access, which offers advantages in power ______ and terminal battery life as compared to technologies used today. The latest antenna technologies will also be used, such as ______ , which employs multiple transmit and receive antennas. This results in numerous data paths effectively operating in ______ and-through appropriate coding/decoding-significant throughput gains.

A:Time B:Frequency C:Code D:Wavelength