The baby is six months old.
その赤ちゃんは６か月だ
the beginning [the end] of the month
月初め［月末］
The ceasefire is meant to last until March.
停戦は３月まで続くことになっている
the circle of the twelve months
１年１２か月の循環
The committee sits once a month.
委員会は月１回開催される
the date of birth ＝the birth date
生年月日
The days went by quickly.
あっという間に月日が過ぎ去った
the first day of April
４月１日
the first days of April
４月早々
the following day [week, month] ＝the day [week, month] following
その翌日［週，月］
