To （）important dates in history, countries create special holidays.

单项选择题Doctors are often caught in a （）because they have to decide whether they should tell their patients the truth or not.

A．puzzle
B．perplexity
C．dilemma
D．bewilderment

单项选择题While a full understanding of what causes the disease may be several years away, （）leading to a successful treatment could come much sooner.

A．a distinction
B．a breakthrough
C．an identification
D．an interpretation