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单项选择题

A．a well-known process.B．a frequent occurrence.C．a flee……

According to the passage, the author considers the reduction of energy in an empty region of space to which a real particle has been added to be


A．a well-known process.
B．a frequent occurrence.
C．a fleeting aberration.
D．an unexpected outcome.
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单项选择题Physicists' recent investigations of the decay of the vacuum, as described in the passage, most closely resemble which of the following hypothetical events in other disciplines

A．On the basis of data gathered in a carefully controlled laboratory experiment, a chemist predicts and then demonstrates the physical properties of a newly synthesized polymer.
B．On the basis of manipulations of macroeconomic theory, an economist predicts that, contrary to accepted economic theory, inflation and unemployment will both decline under conditions of rapid economic growth.
C．on the basis of a rereading of the texts of Jane Austen' s novels, a literary critic suggests that, contrary to accepted literary interpretations, Austen's plots were actually metaphors for political events in early nineteenth-century England.
D．on the basis of data gathered in carefully planned observations of several species of birds, a biologist proposes a modification in the accepted theory of interspecies competition.

单项选择题Which of the following titles best describes the passage as a whole

A．The Vacuum: Its Fluctuations and Decay.
B．The Vacuum: Its Creation and Instability.
C．The Vacuum: A state of Absence.
D．Particles That materialize in the Vacuum.

单项选择题It can be inferred from the passage that scientists are currently making efforts to observe which of the following events

A．The decay of a vacuum in the presence of virtual particles.
B．The decay of a vacuum next to a super heavy atomic nucleus.
C．The creation of a superheavy atomic nucleus next to an intense electric field.
D．The creation of a virtual electron and a virtual positron as a result of fluctuations of a vacuum.

单项选择题From the sentence Like Proust, the French author whose experiences became his literary capital, man can recapture the past. you can tell that Proust

A．wrote primarily to improve his future life.
B．discovered thing about his future life.
C．described man's development of time sense.
D．wrote about past experiences.

单项选择题The word contingencies underlined here means

A．uncertainties.
B．dependent conditions.
C．incidental thought.
D．events that may occur.