1. - Where is Mary?- She _ in the library. A. should be B. must be C. can be D. must have been2. His room is dark. He must _ to bed. A. go B. be going C. have gone D. have been gone3. “Will your father stay home tonight?”“Im not sure, He _to work.” A. must go B. can go C. may be gone D. may be going4.
