下列哪种误差在测量结果中是不能避免的（）
A、系统误差
B、随机误差
C、过失误差
D、人为误差
参考答案：B
--- Long time no see! You look well.
--- ______. You look fine, too.
A．Thanks
B．Great
C．Oh, no
D．Not at all
Look! There is ________ cat in the tree. [ ]
A. a
B. an
C. the
D. /
