1 The passive is preferred in both english and chinese when the agent is unknown and can not be easily specified(明确说明), for example, a. Ten people were killed in the war b.门被撬开了• 1) The passive is preferred in both English and Chinese when the agent is unknown and can not be easily specified（明确说明）, for example, • a. Ten people were killed in the war. • b.门被撬开了