Many languages have both an active and a passive voice; this allows for greater flexibility in sentence construction, as either the semantic agent or patient may take the syntactic role of subject. The use of passive voice allows speakers to organize stretches of discourse by placing figures other than the agent in subject position. This may be done to foreground the patient, recipient, or other thematic role; it may also be useful when the semantic patient is the topic of on-going discussion. The passive voice may also be used to avoid specifying the agent of an action.