To begin to understand why, remember that water in a reservoir naturally flows preferentially to any crack in the dam. 要探究原因，可以联想一下蓄水池的水，当水坝有裂缝时，水很自然的会先由裂缝流出。
These animals act as the reservoir for the rabies virus and for its continued spread. 这些动物担当狂犬病毒的蓄水池并使他们继续传播。
