Mr. Brown has worked in the factory ______15 years.       [ ]

A. for                          

B. before                      

C. of                          

D. since

黄疸的发生往往内外相因为患，从内因来说，主要以下列哪项为主：

A．湿热

B．水饮

C．湿浊

D．瘀血

E．痰浊