食管重度不典型增生：异型上皮几乎累及上皮的2/3以上，细胞大小不一，核异型明显，是癌前病变。
参考答案：错
——Is it my appearance the professor minds?
——I guess not. He will consider necessary to have an experienced assistant.
A．which；it
B．that；it
C．which；that
D．that;that
在我国大多数河流中，当库容系数小于（）时，多为年调节水电站。
A.20%
B.25%
C.30%
D.35%
