默认情况下，ExCel会自动给保存的文件加上（）扩展名。
A.DoC
B.xls
C.exC
D.exl
参考答案：B
When he got home, he would find his house _______ and he didn’t know______ to do with the robot.
A．in a mess, how
B．in a mess, what
C．in mess, what
D．at a mess, how
哪个检查窗主要用于显示左、右椎动脉及两者汇聚而成的基底动脉（）。
A.颞窗
B.枕窗
C.眼窗
D.额窗
E.顶窗
