—I am sorry I stopped outside for a smoke. I was very tired.

—There is no ______ for this while you are on duty.

A．reason　　　　 B．excuse　　　　 C．cause　　 　 D．explanation

------ I’m sorry I stepped outside for a smoke. I was very tired.

------ There is no _____ for this while you are on duty.

A．reason　 　　　 B．excuse　 　　　C．cause　 　　　　 D．explanation

—I’m sorry I stepped outside for a smoke. I was very tired.

　　—There is no ________ for this while you are on duty.

　　A．reason

　　B．excuse

　　C．cause

　　D．explanation

　　—There is no ________ for this while you are on duty.

　　A．reason

　　B．excuse

　　C．cause

　　D．explanation

--- What is the _____ for your being late?

   --- I am sorry I missed the first bus.

  A. reason                        B. excuse                             C. cause                               D. explanation