阅读题
Palpitations are usually reported as a fluttering in the chest or a feeling that the heart has jumped. A person may experience palpitations during times of stress, such as after several days with less sleep than normal, or before a test or an important meeting. Caffeine, nicotine, and medications such as cold tablets may be factors in bringing on the attacks. Another factor is a sudden change of position, such as getting out of bed too quickly or jumping up to answer the telephone. With palpitations, the heartbeat regulator has trouble adjusting to the quick switch from a circulatory system that is horizontal to one that is vertical. The pulse rate must be changed, and because of this, the heart may skip a few beats, similar to the way in which a car motor misses a beat as it goes from driving on a flat road to climbing a hill.
According to the passage, palpitations may result from all of the following EXCEPT
A．anxiety before a test
B．a change in occupation
C．cold medicine
D．standing up quickly
The author compares the heartbeat regulator to
A．an important meeting
B．getting out of bed
C．the telephone
D．the motor of a car
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Palpitations are usually reported as a fluttering in the chest or a feeling that the heart has jumped. A person may experience palpitations during times of stress, such as after several days with less sleep than normal, or before a test or an important meeting. Caffeine, nicotine, and medications such as cold tablets may be factors in bringing on the attacks. Another factor is a sudden change of position, such as getting out of bed too quickly or jumping up to answer the telephone. With palpitations, the heartbeat regulator has trouble adjusting to the quick switch from a circulatory system that is horizontal to one that is vertical. The pulse rate must be changed, and because of this, the heart may skip a few beats, similar to the way in which a car motor misses a beat as it goes from driving on a flat road to climbing a hill.
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