眼底出血的中医辨证，在早期应凉血止血。
参考答案：对
Mr. Black was so____ to his research that he seldom cared about what happened around him.
A．devoted
B．concerned
C．absorbed
D．used
直接作用的化学致癌物是（）
A.烷化剂
B.酰化剂
C.金属元素如镍、铬
D.非金属元素如砷
E.有机化合物如苯
