题目

 Sorry to have kept you waiting so long, but it’ll still be some time ______ Mr. Smith is available.    A. when              B. before                 C. after           D. since 答案：B从所给的四个选项中选择最佳答案 Do you know who ______ at the meeting tomorrow?　　　[　　] A．speaks　　    　B．spoke C．will speak　　　D．has spoken