找考题网-背景图
单项选择题

A．They often take place in her major industries.
B．British trade unions are more powerful.
C．There are more trade union members in Britain.
D．Britain loses more working days through strikes every year.
<上一题 目录 下一题>
热门试题

单项选择题The author's assertions concerning the conditions that lead to the decay of the vacuum would be most weakened if which of the following occurred

A．Scientists created an electric field next to a vacuum, but found that the electric field was not intense enough to create a charged vacuum.
B．Scientists assembled a super heavy atomic nucleus next to a vacuum, but found that no virtual particles were created in the vacuum's region of space.
C．Scientists assembled a super heavy atomic nucleus next to a vacuum, but found that they could not then detect any real particles in the vacuum's region of space.
D．Scientists introduced a virtual electron and a virtual positron into a vacuum's region of space, but found that vacuum did not then fluctuate.

单项选择题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.

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.