溃疡性结肠炎的常见病理改变见（）
A.黏膜弥漫性充血，水肿，出血
B.黏膜溃疡
C.肠穿孔
D.瘘管形成
E.结肠周围脓肿
参考答案：A, B
It is reported that many a new house _____ at present in the disaster area. [ ]
A. are being built
B. were being built
C. was being built
D. is being built
滚动轴承摩擦的接触状态为（）。
A.液体摩擦
B.半液体摩擦
C.半干摩擦
D.干摩擦
