Sie schliefen. Learn Unstarted Literal Breakdown Recording English German Learn they sie Learn slept schliefen Learn Summary The German translation for “They were sleeping.” is Sie schliefen.. The German, Sie schliefen., can be broken down into 2 parts:"they" (sie) and "slept" (schliefen). Practice Lesson "They were sleeping." Practice (3) Lesson Learn Lesson words slept, they etc. View all lesson words Lesson phrases They were sleeping. etc. View all lesson phrases Acknowledgements English source https://lingopolo.org/dutch/word/they-were-sleeping Audio Google text-to-speech