单项选择题

A.
充分条件 B.
必要条件 C.
充要条件 D.
无关条件

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多项选择题

The reservations agent will have tofind out which class of service the passenger desires, that is, ( )
A、first class
B、business class
C、economy class

单项选择题

The most important governing principle is to apply laws to the people.

A．true
B．false