・in the past 過去に.

・in (one's) boyhood [youth, manhood] 少年[青年, 壮年]時代に.

・in January 1 月に.

・in (the) spring [summer, autumn, winter] 春[夏, 秋, 冬]に.

・in the 26th year of Meiji 明治 26 年に.

・in (the year) 1977 1977 年に.

・in the morning [afternoon, evening] 午前[午後, 晩]に.

・He is in his fifties. 50 代だ.

・in the nineties 90 年代に.

・in the day [daytime] 昼間に, 日中に.

・in the night [nighttime] 夜間に, 夜に (cf. at NIGHT).

・in those days その当時.

・I never saw such a man in my life. 私はこれまでそんな人は見たことがない.