一般的酸洗缓蚀剂的缓蚀效率应该在（）以上。
A.70%
B.80%
C.90%
参考答案：C
[2013·安徽高考]设△ABC的内角A，B，C所对边的长分别为a，b，c.若b＋c＝2a,3sinA＝5sinB，则角C＝________.
Most co-workers think him superior ________ the manager though he i.s an ordinary employee. [ ]
A. with
B. by
C. over
D. to
