When a magnet attracts iron filings, or when rubbed amber attracts cotton fibres, the filings, or the fibres are caused to move.
(a magnet; attracts; iron filings) (when rubbed amber; attracts; cotton fibres, the filings, or the fibres)
a magnet when rubbed amber
attracts attracts
iron filings
cotton fibres, the filings, or the fibres