(i) The umpire will be who in tomorrow's match?
(ii) By then, the restaurant will be closed. OR They will have closed the restaurant by then.
In passive sentences the subject is no longer acting, but rather is acted upon. The subject/verb relationship changes. Active sentences are generally more concise and easier to understand than passive sentences. The passive voice may be used when the author wants to emphasize the action in a sentence or when the subject performing the action is unknown or unnecessary.