I am sorry to ( ) you waiting so long

i am sorry to keep you waiting so long I am sorry I _____(keep)you waiting so long. I am sorry you have been waiting so long .BUT I am very sorry for keeping you waiting so long. [D100] I am sorry to _____ you waiting outside so long. i am sorry to keep you waiting for me so long 最佳答句是什么? I'm sorry to keep you waiting so long I'm sorry to have kept you waiting so long. I am sorry to have kept you waiting so long.这句为什么用to have ke I'm sorry to have kept you waiting so long 和i' m sorry to ke I am sorry you have been waiting so long .but it will still I am sorry to keep you waiting for so longA I don't think so