

Ein Wasserkocher ist im Büro wirklich nützlich.
[ˈaɪ̯n ˈvasɐˌkɔxɐ ˈɪst ˈɪm byˈroː ˈvɪrklɪç ˈnʏtslɪç.]
A kettle is really useful in the office.
Danke für den nützlichen Tipp mit dem Eistee!
[ˈdaŋkə ˈfyːɐ̯ ˈdeːn ˈnʏtslɪçn̩ ˈtɪp ˈmɪt ˈdeːm ˈaɪ̯sˌteː!]
Thanks for the useful tip about the iced tea!
Auf Reisen ist eine Thermoskanne am nützlichsten.
[ˈaʊ̯f ˈraɪ̯zn̩ ˈɪst ˈaɪ̯nə ˈtɛrmoːsˌkanə ˈam ˈnʏtslɪçstn̩.]
When traveling, a thermos is the most useful.
"nützlich" is in the lesson "Drinks" (Level 40), along with 11 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.