I. Fill in the blanks with the appropriate transit...

2. Fill in the blanks with the appropriate words（每小题2分，共40分） (1) A 1) is characterized by having a well-structured periodic placement of atoms. The smallest assembly of atoms that can be repeated to form the entire crystal is called a 2) , with a dimension of 3) . (2) For any semiconductor there is a forbidden energy range in which allowed states cannot exist. Energy regions or energy bands are permitted above and below this energy gap. The upper bands are called the 4) ; the lower bands, the 5) . The separation between the energy of the lowest conduction band and that of the highest valence band is called the 6) or energy gap Eg, which is one of the most-important parameters in semiconductor physics. (3) For an n-type silicon, a substitutional phosphorous atom with five valence electrons has replaced a silicon atom and a negative-charged electron is donated to the lattice in the conduction band. The phosphorous atom is called a 7) . When a boron atom with three valence electrons substitutes for a silicon atom, a positive-charged hole is created in the valence band and an additional electron will be accepted to form four covalent bonds around the boron. This is p-type, and the boron is an 8) . We can calculate the approximate distance of the donor electron from the donor impurity ion, and also the approximate energy required to elevate the donor electron into the conduction band. This energy is referred to as the 9) . (4) Electronic devices rely on transport of electrons (holes) in materials. This transport occurs either under the influence of an electric 10) or carrier concentration 11) . There are two collision or scattering mechanisms that dominate in a semiconductor and affect the carrier 12) : phonon or 13) scattering, and 14) scattering. If the carrier energy is large enough it can transfer energy to the lattice by the emission of an optical phonon. This mechanism is very efficient and limits the maximum drift velocity. The limiting value for the drift velocity is termed the 15) . Besides the 16) , which flows when an electric field is applied and which follows Ohm's law, an additional important component of current can flow if a spatial variation of carrier energies or densities exists within the material. This component of current is called 17) . (5) The bipolar transistor has three separately doped regions and two pn 18) . The three terminal connections are called the emitter, base, and 19) . The width of the 20) region is small compared to the minority carrier diffusion length.

Fill in each of the blanks with an appropriate word. Nowadays there is a media trend toward diminishing the importance of fathers in the United States. On the one hand, we have easy access to 1) stories about the struggles of working mothers. On the other, the 2) of fathers presented in the media are always 3) or irresponsible. Fathers are usually blamed for not helping much with the housework. Compared with working mothers and at-home dads, working fathers have received less media attention, although most are quietly yet proudly 4) their family duties. Our society has given little cultural 5) to those breadwinner fathers. Recently, there is another media trend of regarding at-home wives as “6) symbols” — a luxury not many men can afford to have. In fact, men as sole wage earners suffer many 7) . They have to work extra hours to make more money to support their families. It would be wise for us to be 8) of the importance of fathers to their children. It would also be advisable for us to recognize the great efforts that fathers make to support their families. They, the unsung heroes, 9) our recognition and our thanks for what they do. 1)

Choose the appropriate time signals to fill in the blanks. (choose only one correct answer) (), he received a film camera as his birthday present. (), he became increasingly interested in cinematography. After 13 years of relentless pursuit of his beloved cause, he won himself a seven-year contract with Universal Studios where he strove hard and produced numerous notable movies. (), he revealed that his lifelong conviction was to “Make sure you are right and go on!”, which has immensely inspired the young with the dream of film.

A、When Steven was eight years old;As the renowned movie director; Since then

B、When Steven was eight years old; Since then; As the renowned movie director

C、Since then; As the renowned movie director; When Steven was eight years old

D、 As the renowned movie director; Since then; When Steven was eight years old

一、 Fill in the blank in each sentence with an appropriate prefix or suffix. （填空每题2分，共10分） 1. _____ organic chemistry is the scientific study of chemical substances which do not contain carbon. 2. The railway system that has a single rail, or the train that travels along it is technically called ______ rail. 3. Some types of _______ biotic are used to promote growth in farm animals. 4. According to this report, in the last 50 years there has been a 33-______ increase in the amount of pesticide used in farming. 5. Opposite to the ______ centric model of the solar system, Copernicus suggested a model in which the sun was central.

A、Moreover…without

B、Nevertheless…whereas

C、In addition…in spite of

D、However… despite