

Ich gehe einmal pro Woche schwimmen.
[ˈɪç ˈɡeːə ˈaɪ̯nmaːl ˈproː ˈvɔxə ˈʃvɪmən.]
I go swimming once a week.
Ich war erst einmal in Berlin.
[ˈɪç ˈvaːɐ̯ ˈeːɐ̯st ˈaɪ̯nmaːl ˈɪn bɛrˈliːn.]
I've only been to Berlin once.
Wir essen nur einmal am Tag warm.
[ˈviːɐ̯ ˈɛsn̩ ˈnuːɐ̯ ˈaɪ̯nmaːl ˈam ˈtaːk ˈvarm.]
We only eat a hot meal once a day.
"einmal" is in the lesson "Time 3" (Level 40), along with 13 other useful words. LinDuo has 180 topic lessons like this one, 2,375 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.