Voice
The voice of a verb can be either active or passive. The active voice is the most common and preferred in English usage. In an active clause the subject and object of the main verb are in their usual position, i.e. SVO, ‘Alex caught the thief’ however, in a passive sentence, the object is transferred to the subject position, e.g. ‘The thief was caught by Alex.’ This can have the effect of emphasising the object or diminishing the effect of the subject. in fact, in a passive construction, the subject can be hidden completely, e.g. ‘The thief was caught.’