But somehow I got my days mixed up and didn't realize the mistake until now.
可是不知道怎么回事,我把日期弄错了,而且到现在才知道这个错误。
Those planning a trip to remote areas, or intending to live in countries where drinking water is not readily available, should know about the various possible methods for making water safe.
那些计划去偏远地区旅行,或在饮用水不现成的国家居住的人,应该知道如何使水适于饮用的各种办法。