下面哪项不是IPTV的三个基本业务（）。
A.视频点播
B.直播电视
C.时移电视
D.IPTV可视电话
参考答案：D
We were all surprised when he made it clear that he ____ office soon.[ ]
A. leaves
B. would leave
C. will leave
D. had left
指纹鉴定的基本步骤是什么？
