Past continuous vs. past simple
Deze zinnen kun je herkennen aan het woordje 'when':
''When the phone rang, she was writing a letter.''
'' What were you doing when the earthquake started?''
Als het woordje 'while' in de zin staat, gebeuren twee dingen tegelijk.
Dan gebruik je twee keer de past continuous:
''What were you doing while you were waiting?''
''I was studying while my father was making dinner.''