慢性支气管炎发展成阻塞性肺气肿的过程中最先发生的病理改变是()。
A.肺泡膨胀
B.细支气管不完全阻塞
C.肺泡壁弹性减退
D.肺小动脉痉挛
E.肺纤维化
参考答案:B
When the old man_____to walk back to his house,the sun____itself behind the mountain.
A.was starting;hid
B.had started;had already hidden
C.had started;was hiding
D.started;had already hidden
华誉养鸡场一房内有公鸡65只,母鸡只数是公鸡的7倍,这个房内共有多少只鸡?