For a MOSFET, the threshold voltage is a voltage required for

The first is broadly the way Britain is at the moment: a mosaic of communities--Bangladeshi, Afro- Caribbean, Chinese or Jewish holding fast to a strong social identity, but lumbered also with a whole raft of benefits and disadvantages, most of them defined in economic terms l6. It's possible that will still be the pattern in 50 years time, but not very likely.

……

The alternative is a pick-and-mix social landscape. At the moment ethnic minorities are moving in different directions at different rates, with personal and social engagement across ethnic boundaries increasing all the time. One crude indicator is the level of mixed race marriage: one in five Bangladeshi and Pakistani men born in Britain now has a white wife, and one in five babies born in Britain has one Afro-Caribbean and one white parent.

This implies a Britain in which people will construct multiple identities defined by all sorts of factors: class, ethnicity, gender, religion, profession, culture and economic position. It won't be clear-cut. Not all ethnic minorities, or members of an ethnic minority, will be moving in the same direction or identifying the same issues at the heart of their identities. It's about deciding who you are, but also about how other people define you.

That's what will be at the heart of the next 50 years: enduring communities linked by blood through time versus flexible, constantly shifting identities. Identity won't be about where you have come from; it will be a set of values you can take anywhere that is compatible with full participation in whichever society you live in.

听力原文： As is known to all, scientists and philosophers had studied the human body and its functions from very early times. Unfortunately, many of the ideas and theories, correct and incorrect, were accepted without question for a great number of years. But by the 16th century, knowledge gained through chemical experiments was beginning to make some people think more deeply about how the human body works.

A most important medical discovery was made by William Harvey in 1628. He found out that the blood is circulated round the body in one direction only by the pumping action of the heart. It had previously been incorrectly thought that the blood moved with a backward and forward motion.

Early in the 17th century a new instrument came into use that was to open up a whole new area in the study of medical and scientific matters. This was the microscope.

The first instruments were not very efficient. They were able to magnify only a very small part of the object and this was always surrounded by rings of coloured light. Nevertheless a great step forward had been taken which was of vital importance for future research and development.

(30)

A．Scientists and philosophers bad never studied the human body and its functions.

B．Many of the ideas and theories that people used to accept were all incorrect.

C．People used to accept ideas and theories.

D．People used to accept undoubtedly many of the ideas and' theories, correct and incorrect.

听力原文： As is known to all, scientists and philosophers had studied the human body and its functions from very early times. Unfortunately, many of the ideas and theories, correct and incorrect, were accepted without question for a great number of years. But by the 16th century, knowledge gained through chemical experiments was beginning to make some people think more deeply about how the human body works.

A most important medical discovery was made by William Harvey in 1628. He found out that the blood is circulated round the body in one direction only by the pumping action of the heart. It had previously been incorrectly thought that the blood moved with a backward and forward motion.

Early in the 17th century a new instrument came into use that was to open up a whole new area in the study of medical and scientific matters. This was the microscope.

The first instruments were not very efficient. They were able to magnify only a very small part of the object and this was always surrounded by rings of colored light. Nevertheless a great step forward had been taken which was of vital importance for future research and development.

(30)

A．Scientists and philosophers had never studied the human body and its functions.

B．Many of the ideas and theories that people used to accept were all incorrect.

C．People used to accept ideas and theories.

D．People used to accept undoubtedly many of the ideas and theories, correct and incorrect.

听力原文： As is known to all, scientists and philosophers had studied the human body and its functions from very early times. Unfortunately, many of the ideas and theories, correct and incorrect, were accepted without question for a great number of years. But by the 16th century, knowledge gained through chemical experiments was beginning to make some people think more deeply about how the human body works.

A most important medical discovery was made by William Harvey in 1628. He found out that the blood is circulated round the body in one direction only by the pumping action of the heart. It had previously been incorrectly thought that the blood moved with a backward and forward motion.

Early in the 17th century a new instrument came into use that was to open up a whole new area in the study of medical and scientific matters. This was the microscope.

The first instruments were not very efficient. They were able to magnify only a very small part of the object and this was always surrounded by rings of colored light. Nevertheless a great step forward had been taken which was of vital importance for future research and development.

(30)

A．Scientists and philosophers had never studied the human body and its functions.

B．Many of the ideas and theories that people used to accept were all incorrect.

C．People used to accept ideas and theories.

D．People used to accept undoubtedly many of the ideas and theories, correct and incorrect.

听力原文： Mosquitoes do not randomly perch on just anyone's body and begin sucking for the most fragrantly appealing humans. Mosquitoes use odor to sort attractive people from the unattractive to find those that are most tasty.

Researchers found one sure way to stop attracting the little bugs--stop breathing. Mosquitoes can sniff out an attractive target from as far as 40 miles. When humans exhale, they expel a plume of C02 and other odors that travel through the air. The appetizing stir is the equivalent of a dinner bell, alerting mosquitoes that a warm meal is within range.

When a mosquito is trailing an attractive target, it zigzags up the breath plume until it makes contact, landing on the skin and patiently searching for just the right spot to insert its styled for an eight-to-ten second feeding.

Perspiration, a barely avoidable human condition, also is a mosquito lure--but only if the sweat has formed bacteria.

Bathing helps reduce the attractiveness of sticky bodies, but after-bath products don't. Skin-care products that clean, soften and moisturize not only improve a person's appearance, they're also attractive to mosquitoes. ) Certain medications, including heart and blood pressure medicine, also alter a person's likelihood of being bitten.

Scientists conducted the research to explore the tastes of mosquitoes and help humans protect themselves from mosquito-borne disease.

All of the following are causes of being bitten by mosquitoes EXCEPT______.

A．carbon dioxide and other odors

B．sweat

C．the quality of your skin

D．heart and blood pressure medicine