Complex sentence: The 24-hour clock notation avoids these ambiguities by using 00:00 for midnight at the start of the day and 12:00 for noon and for midnight at the end of a day.
Split into simpler sentences: The 24-hour clock notation avoids these ambiguities by using 00:00 for midnight at the start of the day and 12:00 for noon. In 24-hour notation can be used to refer to midnight at the end of a day.