.Where is your father?- Im not sure. He in the office.A. must beB. maybeC. may beD

问题补充：

.--- Where is your father?

--- Im not sure. He in the office.

A. must be

B. maybe

C. may be

D. perhaps

答案：

A. must be

B. maybe

(答案→)C. may be

D. perhaps

解析：句意：---你父亲在哪里？---我不确定。他可能在办公室。must be一定是，表示对现在事实的推测；maybe副词，可能，大概，也许；may be可能是，表示对现在的可能性推测；perhaps副词，可能，大概，也许。因为空后无任何系动词或实义动词，故需填情态动词+be结构，有因为题干中有Im not sure表示不确定的成分，故选C。