单项选择题

What is NOT true about a theory

A．A useful theory can explain past observations.
B．A useful theory helps to make predictions.
C．A theory is the truth that does not need to be tested.
D．A theory may have to be revised or rejected some times.

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热门试题

单项选择题

In Paragraph 5, the author refers to a hypothesis as a leap into the unknown in order to show that hypotheses ______.

A．go beyond available facts
B．are sometimes ill-conceived
C．can lead to dangerous results
D．require efforts to formulate

单项选择题

The author says, There was one thing that went wrong with my experiment. What was the one thing that went wrong

A．He praised her sweater, which puzzled her.
B．She insisted on visiting a museum, which he hated.
C．He knew something about her illness but didn't tell her.
D．He was so good to her that she thought she must be dying.