A ring round the moon means rain.
月にかさがかかると雨になる
a rocket voyage to the moon
月へのロケット旅行
a three-month-old baby = a baby of three months
3か月の赤ちゃん
a train pass valid for three months
3か月有効な定期券
a two-month TV program
2か月続くテレビ番組
a two-month-old magazine
2か月前の雑誌
a week (from) Monday
来週の月曜日(((英))Monday week)(◆next Mondayの方がふつう)
a week ago last Monday
先々週の月曜日(((英))a week last Monday)
a week ago Monday
先週の月曜日(((英))a week on Monday)
a weekly [monthly, literary] magazine
週刊[月刊,文芸]雑誌