单项选择题
A．the Nairobi city government B．the police of the Nairobi Airport C．the organizer of the seminar D．Kennedy Hongo, a detective
A．have never made any mistakes B．often make mistakes but correct them in no time C．admit their mistakes D．forget other people’s mistakes easily
A．not at all useful B．very helpful for a while C．necessary for staying free D．important and useful