Now the man （ ）① see people passing by.He knew it was only a

Now the man （ ）① see people passing by.He knew it was only a metter ( )② time before another one came to him.To avoid (避免） the problem ,he got out a pen and paper and ( )③ a sign on his window .It read ,"I do not know the time " Then a few minutes ( )④ there was another knock on the window."Sir,sir It's 8:45!"
①A.should B.could C.had to D.must
②A.for B.of C.as D.at
③A.put B.kept C.wrote D.planned
④.A.ago B.before C.later D.early