影响风蚀的因素？
参考答案：
土壤抗蚀性；地表土垄；降雨；土丘坡度；裸露地块长度；植被覆盖。
When we returned from our holidays, we found everything ____. What ____ while we had
been away? [ ]
A. changed ; had happened
B. changing ; happened
C. had changed;has happened
D. was changing; happened
男，32岁，反复咳嗽咳痰多年，加重3个月，伴咯血10天，CT示左下肺串珠状软组织结节影，可见一小液平，最可能的诊断是
A．肺支气管动静脉瘘
B．癌性淋巴管炎
C．支气管扩张症
D．支气管肺癌
E．肺内转移癌
