It is hard to say what kind of person he is. Sometimes he is very friendly;  at other times he ___ be very cold. [ ]

A. can

B. must

C. will

D. shall

在PowerPoint编辑状态下，不能插入一张新幻灯片的操作是 (64) 。

A．单击[常用]工具栏中的[新建]按钮

B．按[Ctrl+M]组合键

C．单击[格式]工具栏中的[新幻灯片]按钮

D．选择[插入]→[新幻灯片]命令