各种黄疸患者尿液中易见（）
A.胆红素结晶
B.胱氨酸结晶
C.酪氨酸结晶
D.亮氨酸结晶
E.胆固醇结晶
参考答案：A
心绞痛疼痛的性质是（）
A.刀割样痛
B.烧灼样痛
C.绞榨样痛
D.撕裂样痛
E.隐痛
There is something______they have learned from scientific study. [ ]
A. which
B. who
C. where
D. that
