分离含羰基的甾体皂苷元，可用（）
A.乙醚萃取法
B.乙醚沉淀法
C.丙酮沉淀法
D.胆甾醇沉淀法
E.吉拉尔试剂法
参考答案：E
When people want to relax themselves, they prefer TV or listen to music rather
than newspapers.
A．watching; read
B．watching; to read
C．to watch; read
D．to watch; reading
试述莱姆病的诊断依据。
