請依下文回答第 46 題至第 50 題 There is no denying that advanced firefighting involves not just the direct suppression of a fire but also the general
knowledge of the theoretical framework of the process. The latter includes understanding the principles and
methodologies behind the management and suppression of fires. To stop a conflagration, one needs to be aware of the
concept of the combustion triangle, which presupposes that a conflagration needs three distinct components. Specifically,
the latter would be a source of heat, oxygen, and a physical piece of burning material. As soon as the practitioner
understands these premises, he or she may use various ways to convert them into methods of further fire suppression.
One should note that the behavior of fires is dynamic and includes the ignition, propagation, and combustion phases.
Therefore, a firefighter has to learn how to approach each activity since fires may be continuous or smoldering, as well
as vary in heat content or speed. Additionally, it is also crucial to understand that the conflagrations may belong to
different kinds and have unique properties, based on their sources. They can begin from electrical wires, kitchen frying
pans filled with hot oil, or even various chemical substances. Consequently, concerning the verbal categorization of
firefighting tactics, firefighters may oscillate between either offensive or defensive measures. The former includes the
methods that allow suppressing the flames and materials directly and quickly. At the same time, defensive tactics are
performed to put a perimeter around the fire and stop its spread to other objects in the area. Finally, it is also important
to mention that ventilatory tactics are critical to adjust the inflow-outflow balance of gases in a building to avoid
backdrafts.
【題組】50 Which of the following words is closest in meaning to “oscillate”?
(A) Swing.
(B) Persist.
(C) Stabilize.
(D) Halt.