结合超声图像,肾脏积水最常见的原因是()
A.输尿管结石
B.输尿管囊肿
C.输尿管肿瘤
D.输尿管脱垂
E.输尿管先天畸形
参考答案:A
My aunt has a nice house _____ many trees and flowers around it. [ ]
A. has
B. is
C. and
D. with
缩聚反应除生成高聚物外,同时还生成小分子物质。