[单项选择]

Most of the pioneers of low-temperature physics expected gases to liquefy, but none of them predicted superconductivity. This phenomenon was discovered in 1911 by Onnes while he was studying frozen mercury.
More than 40 years passed before physicists were able to offer an explanation for superconductivity. The accepted theory, developed in the 1950s, holds that the fundamental behavior of electrons changes at very low temperatures because of the effects of quantum mechanics. Electrons are tiny particles that make up the outer part of an atom, circling rapidly around the nucleus of the atom. In a regular conductor—a metal that conducts an electric current—the outermost electrons are not bound tightly to the atoms, and so they move around relatively freely. The flow of these electrons is an electric current.
At normal temperatures, a conductor’s electrons cannot move completely freely through the metal because they are "bumped around" by
A. electrons do not move freely through the metal
B. electrons are crowded together
C. paired electrons move uninterruptedly
D. paired electron dance together to and fro

[单项选择]

Most of the pioneers of low-temperature physics expected gases to liquefy, but none of them predicted superconductivity. This phenomenon was discovered in 1911 by Onnes while he was studying frozen mercury.
More than 40 years passed before physicists were able to offer an explanation for superconductivity. The accepted theory, developed in the 1950s, holds that the fundamental behavior of electrons changes at very low temperatures because of the effects of quantum mechanics. Electrons are tiny particles that make up the outer part of an atom, circling rapidly around the nucleus of the atom. In a regular conductor—a metal that conducts an electric current—the outermost electrons are not bound tightly to the atoms, and so they move around relatively freely. The flow of these electrons is an electric current.
At normal temperatures, a conductor’s electrons cannot move completely freely through the metal because they are "bumped around" by
A. electrons circle rapidly around the atom
B. the outermost electron move relatively freely around the atom
C. the innermost electrons stick to the atom
D. the outermost electrons are bound tightly to the inner ones

[填空题]According to consumer behaviorists, most people experience the same kinds of needs and motives______.

[单项选择]Children’s fears come and go, but most children experience similar types of fears at approximately the same age. For toddlers, the worst fears are often associated with separation and change. Toddlers want their own mommy, daddy, .spoon, chair, and bed. They are profoundly conservative little people. The most daring toddlers feel content if they can hold onto what they already know. Yet, children’s fears are a useful index of their development. Fear of strangers appears to be a consequence of their first specific attachment, and its ending is a sign that they have acquired a more inclusive schema of faces and people in general. A child who is afraid of cats but not of rabbits evidently can differentiate one small animal from another. Fear of a particular person implies recognition of that person.
Parents can be of assistance, both in overcoming fears and in preventing their development. They can prepare a child through play, stories, and happy prognostications for dealing with new
A. An indicator or measurement of something.
B. A list or catalog of information.
C. An object used to point or indicate.
D. A relation or ratio of one quantity to another.

[填空题]RealNetworks was one of the pioneers in Intemet audio. It was the first one to (26) streaming audio over the Web. So you might suppose that the latest (27) of its media player, RealPlayer 10, has all- (28) audio capabilities.
The player supports (29) any audio file type you can think of, including MP3, WAV and WMA, and copying these files fi-om your PC’s hard drive into the player is as simple as clicking a couple of buttons. Once you finish, you can instruct the player to watch for new clips arriving on your hard drive and (30) import them into the library.
The player plays other audio clips, as well. Play audio CDs or sync up your iPod or other (31) media player to hear those songs. Listen to a variety of rock, (32) , blues, and news radio stations from within the player.
The high-quality and near-universal playback (33) to video as well. Playback is crisp and clear, and the p