に
At, on, in (a point in time)machine translation
FormationTime word + に
に goes after a time word to say an action happens "at" that time: 七時に起きます (get up at 7), 日曜日に行きます (go on Sunday).
Easy rule to remember: specific times on the calendar or the clock (hours, days of the week, dates) take に; relative words like 今日 (today), 明日 (tomorrow), 毎日 (every day) do NOT take に — say 明日行きます, not 明日に行きます.
To give only an approximate time, use ごろ: 七時ごろ帰ります (get home around 7).
Examples
毎朝六時に起きます。
I get up at 6 every morning.
日曜日に友達と会います。
I'm meeting a friend on Sunday.
授業は九時に始まります。
Class starts at 9.