关于卵巢瘤样病变下列哪项错误（）
A.是一种恶性肿瘤
B.单侧多见
C.直径一般小于8cm
D.壁薄
E.2个月可自行消失
参考答案：A
he head of the company promised to deal with matters of this sort ________ he returned to his office. [ ]
A. until
B. while
C. by the time
D. the moment
采用胶圈接口时，纵坡大于（）时，应采取防止管道下滑的措施。
A.10%
B.15%
C.18％
D.20%
